Aimathic
Login | English | Deutsch

Free Math Worksheets

Build your own math worksheets from 21,000 problems for grades 3 to 12, from fractions to calculus. Every problem includes step-by-step solutions.

Sample spaces for compound events

Click problems to add them to your worksheet.

5140727
The sample space \(S\) is the set of all possible outcomes of a random experiment. Write the sample space for each experiment: a) A fair spinner with four equal sections colored red (R), blue (B), yellow (Y), and green (G) is spun once. b) A coin with heads (H) and tails (T) is flipped twice. c) One number card is drawn from a bag containing cards labeled \(1\), \(3\), \(5\), and \(7\).

Hints

- Imagine performing each experiment. What could be recorded at the end? - For a multistep experiment, include every ordered combination of the stage outcomes. - Write sample spaces using braces and separate outcomes with commas.

Solution

1. a) One spin can result in any of the four colors, so \(S = \{\mathrm{R}, \mathrm{B}, \mathrm{Y}, \mathrm{G}\}\). 2. b) Each outcome records the first and second flips in order. Therefore, \(S = \{(\mathrm{H}, \mathrm{H}), (\mathrm{H}, \mathrm{T}), (\mathrm{T}, \mathrm{H}), (\mathrm{T}, \mathrm{T})\}\). 3. c) The possible outcomes are the labels on the cards, so \(S = \{1, 3, 5, 7\}\).

Answer

a) \(S = \{\mathrm{R}, \mathrm{B}, \mathrm{Y}, \mathrm{G}\}\) b) \(S = \{(\mathrm{H}, \mathrm{H}), (\mathrm{H}, \mathrm{T}), (\mathrm{T}, \mathrm{H}), (\mathrm{T}, \mathrm{T})\}\) c) \(S = \{1, 3, 5, 7\}\)
5172307
Luca has exactly four coins. Every coin is either a penny or a nickel. What different total amounts are possible? List all of them.

Hints

- List the possible numbers of nickels from \(0\) through \(4\). - For each case, the rest of the four coins must be pennies. - Calculate the total value for each composition.

Solution

1. The number of nickels can be \(0,1,2,3,\) or \(4\). The remaining coins are pennies. 2. With \(0\) nickels and \(4\) pennies, the total is \(\$0.04\). 3. With \(1,2,3,\) or \(4\) nickels, the totals are \(\$0.08\), \(\$0.12\), \(\$0.16\), and \(\$0.20\), respectively. 4. These five cases include every possible composition of four coins.

Answer

\(\$0.04\), \(\$0.08\), \(\$0.12\), \(\$0.16\), and \(\$0.20\)
5198637
Four balloons are arranged in a row on a string. There is one red balloon and three identical blue balloons. Use a tree diagram or organized list to determine how many distinct arrangements are possible.

Hints

- Consider each possible position for the one red balloon. - Once the red balloon is placed, what colors must fill the remaining positions? - Each path in a tree diagram corresponds to one completed arrangement.

Solution

1. The red balloon can occupy the first, second, third, or fourth position. 2. These choices produce the arrangements RBBB, BRBB, BBRB, and BBBR. 3. Therefore, there are \(4\) distinct arrangements.

Answer

\(4\) arrangements
5211547
You have a balance scale and three weights with masses \(5\,\text{g}\), \(10\,\text{g}\), and \(50\,\text{g}\). The object being measured must be on one pan, and any weights used must all be on the other pan. What different masses can you measure? List all possibilities.

Hints

- First list the masses measurable with one weight. - Then list every pair of weights. - Include the case that uses all three weights. - Organize the combinations so none are missed.

Solution

1. Using one weight gives \(5\,\text{g}\), \(10\,\text{g}\), or \(50\,\text{g}\). 2. Using two weights gives \(5+10=15\,\text{g}\), \(5+50=55\,\text{g}\), or \(10+50=60\,\text{g}\). 3. Using all three weights gives \(5+10+50=65\,\text{g}\). 4. These are all nonempty combinations of the three weights, so the measurable masses are \(5,10,15,50,55,60,\) and \(65\) grams.

Answer

\(5\,\text{g}\), \(10\,\text{g}\), \(15\,\text{g}\), \(50\,\text{g}\), \(55\,\text{g}\), \(60\,\text{g}\), and \(65\,\text{g}\)
5361487
A bag contains six lettered balls that spell BANANA: B, A, N, A, N, A. One ball is drawn, replaced, and then a second ball is drawn. a) Find the probability of drawing the letter sequence “AN.” b) Find the probability of drawing “AA.”
Figure for problem 536148

Hints

- Count how many balls show each letter. - Find the probability of each letter on one draw. - Replacement means the probabilities do not change. - Multiply the probabilities in the stated order.

Solution

1. There are three balls labeled A, two labeled N, and one labeled B. Thus, \(P(A)=\frac{3}{6}=\frac{1}{2}\) and \(P(N)=\frac{2}{6}=\frac{1}{3}\). 2. Because the first ball is replaced, the probabilities stay the same on the second draw. Therefore, \(P(\text{AN})=\frac{1}{2}\cdot\frac{1}{3}=\frac{1}{6}\). 3. Similarly, \(P(\text{AA})=\frac{1}{2}\cdot\frac{1}{2}=\frac{1}{4}\).

Answer

a) \(\frac{1}{6}\) b) \(\frac{1}{4}\)
5361497
An urn contains \(2\) red balls and \(3\) blue balls. A ball is drawn, replaced, and the urn is mixed before the next draw. This process is repeated three times. Find the probability of drawing exactly two red balls.
Figure for problem 536149

Hints

- List the ordered outcomes with exactly two red draws. - Because the ball is replaced, the probabilities stay the same on every draw. - Determine how many red and blue results each favorable outcome must contain.

Solution

1. On each draw, \(P(\text{red})=\frac{2}{5}=0.4\) and \(P(\text{blue})=\frac{3}{5}=0.6\). 2. The ordered outcomes with exactly two red balls are red-red-blue, red-blue-red, and blue-red-red. 3. Each has probability \(0.4\cdot 0.4\cdot 0.6=0.096\). 4. Therefore, the total probability is \(3\cdot 0.096=0.288\).

Answer

\(0.288\), or \(28.8\%\)
5361507
A bag contains five balls labeled \(1\) through \(5\). A ball is drawn, replaced, and then a second ball is drawn. Find the probability that the sum of the two numbers is greater than \(8\).
Figure for problem 536150

Hints

- List the possible ordered pairs. - Identify the pairs whose sum is greater than \(8\). - Divide the number of favorable pairs by the total number of equally likely pairs.

Solution

1. There are \(5\cdot 5=25\) equally likely ordered pairs. 2. The pairs with a sum greater than \(8\) are \((4, 5)\), \((5, 4)\), and \((5, 5)\). 3. Therefore, \(P(\text{sum greater than }8)=\frac{3}{25}=12\%\).

Answer

\(\frac{3}{25}=12\%\)
5374937
A fair coin is flipped twice. Write the sample space and find the probability of getting exactly one head.
Figure for problem 537493

Hints

- List all ordered outcomes systematically. - Which outcomes contain exactly one H?

Solution

1. The sample space is \(S = \{\mathrm{HH}, \mathrm{HT}, \mathrm{TH}, \mathrm{TT}\}\). 2. The favorable outcomes are \(\mathrm{HT}\) and \(\mathrm{TH}\). 3. Therefore, \(P(\text{exactly one head}) = \frac{2}{4} = \frac{1}{2}\).

Answer

\(S = \{\mathrm{HH}, \mathrm{HT}, \mathrm{TH}, \mathrm{TT}\}\); the probability is \(\frac{1}{2}\).
5374947
A spinner has three equal sections labeled red, blue, and green. After one spin, a fair coin is flipped. What is the probability of the event “blue or tails”?
Figure for problem 537494

Hints

- List all ordered combinations of a color and a coin result. - Do not count the blue-and-tails outcome twice.

Solution

1. There are \(3 \cdot 2 = 6\) equally likely ordered outcomes. 2. The favorable outcomes are \((\text{blue}, \text{heads})\), \((\text{blue}, \text{tails})\), \((\text{red}, \text{tails})\), and \((\text{green}, \text{tails})\). 3. Therefore, \(P(\text{blue or tails}) = \frac{4}{6} = \frac{2}{3}\).

Answer

\(\frac{2}{3}\)
5375117
A random code consists of one letter from \(\{A, B, C\}\) followed by one digit from \(\{1, 2\}\). All six codes are equally likely. Find the probability that the code does not begin with \(A\) and ends in \(2\).
Figure for problem 537511

Hints

- Identify the choices that satisfy each condition. - Count the endpoints that satisfy both conditions.

Solution

1. The six equally likely codes are represented by the six endpoints of the tree. 2. The codes that do not begin with \(A\) and end in \(2\) are \(B2\) and \(C2\), so there are \(2\) favorable outcomes. 3. Therefore, \(P = \frac{2}{6} = \frac{1}{3}\).

Answer

\(\frac{1}{3}\)
5375227
A fair coin is flipped twice. In the tree diagram, H means heads and T means tails. Write a simple event that describes the three selected outcomes, and state its complement.
Figure for problem 537522

Hints

- Find one description shared by all selected outcomes. - Which single outcome is not selected?

Solution

1. The selected outcomes are \(HH\), \(HT\), and \(TH\). 2. A common description is “at least one head.” 3. Its complement is “no heads,” which is the outcome \(TT\).

Answer

Event: at least one head Complement: no heads, or \(TT\)
5136557
Two fair six-sided number cubes are rolled. Consider two ways to record the result. a) The result is the sum of the two numbers. Are the possible sums equally likely? Justify your answer by comparing the probabilities of sums \(2\) and \(7\). b) The result is the ordered pair \((x, y)\), where \(x\) is the result on the first number cube and \(y\) is the result on the second. Explain why the ordered pairs are equally likely, and state the number of outcomes in the sample space \(S\).

Hints

- Count the ordered pairs that produce each sum. - A \(6 \times 6\) outcome grid contains all ordered pairs. - Distinguish between a sum and the ordered pair that produces it.

Solution

1. a) A sum of \(2\) occurs only with \((1, 1)\), so \(P(2) = \frac{1}{36}\). A sum of \(7\) occurs with \((1, 6)\), \((2, 5)\), \((3, 4)\), \((4, 3)\), \((5, 2)\), and \((6, 1)\), so \(P(7) = \frac{6}{36} = \frac{1}{6}\). The sums are not equally likely. 2. b) Each ordered pair combines one of \(6\) results on the first cube with one of \(6\) results on the second. There are \(6 \cdot 6 = 36\) ordered pairs. 3. A \(6 \times 6\) outcome grid has one cell for each ordered pair, and the fair number cubes make these \(36\) cells equally likely. Therefore, each ordered pair has probability \(\frac{1}{36}\).

Answer

a) No. \(P(2) = \frac{1}{36}\), while \(P(7) = \frac{6}{36} = \frac{1}{6}\). b) Yes. There are \(36\) ordered pairs, and each has probability \(\frac{1}{36}\).
5136607
A spinner is divided into \(10\) equal sections: \(7\) blue and \(3\) yellow. The spinner is spun twice. a) Find the probability of the ordered result \((\text{blue}, \text{blue})\). b) A student says, “There are four possible color combinations: \((\text{blue}, \text{blue})\), \((\text{blue}, \text{yellow})\), \((\text{yellow}, \text{blue})\), and \((\text{yellow}, \text{yellow})\). Therefore, each combination has probability \(25\%\).” Explain why this reasoning is incorrect.

Hints

- Count the blue and yellow sections on one spin. - A \(10 \times 10\) outcome grid represents the equally likely ordered section pairs for two spins. - Compare how many section pairs belong to each color combination.

Solution

1. Each spin can land on one of \(10\) equal sections, so a \(10 \times 10\) outcome grid has \(100\) equally likely ordered section pairs. 2. a) There are \(7\) blue choices on the first spin and \(7\) blue choices on the second, giving \(7 \cdot 7 = 49\) blue-blue section pairs. Therefore, \(P(\text{blue}, \text{blue}) = \frac{49}{100} = 0.49 = 49\%\). 3. b) The four color combinations group different numbers of equally likely section pairs. Blue-blue has \(49\) pairs, blue-yellow has \(7 \cdot 3 = 21\), yellow-blue has \(3 \cdot 7 = 21\), and yellow-yellow has \(3 \cdot 3 = 9\). Therefore, the four color combinations are not equally likely.

Answer

a) \(0.49 = 49\%\) b) The four combinations are not equally likely because blue and yellow are not equally likely on a single spin.
5136627
An opaque bag contains \(10\) balls that are either black or white. To estimate the composition, a ball is drawn, its color is recorded, and the ball is replaced. In \(200\) draws, black appears \(124\) times and white appears \(76\) times. a) Based on the results, estimate the number of black balls in the bag. Explain your estimate. b) Suppose the bag actually contains \(6\) black balls and \(4\) white balls. If two balls are drawn with replacement, what is the theoretical probability of drawing exactly one black ball and one white ball?

Hints

- Use the experimental proportion of black balls to estimate the proportion in the bag. - Scale the estimated proportion to a total of \(10\) balls. - For part b, include both possible color orders.

Solution

1. a) The relative frequency of black is \(\frac{124}{200} = 0.62\). 2. Multiplying this estimated proportion by the \(10\) balls gives \(10 \cdot 0.62 = 6.2\). Because the number of balls must be a whole number, a reasonable estimate is \(6\) black balls. 3. b) With replacement, there are \(10 \cdot 10 = 100\) equally likely ordered pairs of ball draws. 4. Black then white can occur in \(6 \cdot 4 = 24\) ordered outcomes, and white then black can occur in \(4 \cdot 6 = 24\) ordered outcomes. Thus there are \(48\) favorable outcomes, so \(P = \frac{48}{100} = 0.48\).

Answer

a) About \(6\) black balls b) \(0.48 = 48\%\)
5140677
A three-digit number is formed by independently choosing either \(1\) or \(2\), with equal probability, for each digit. 1. List every outcome in the sample space \(S\). 2. Event \(G\) is: “The number contains the digit \(1\) at least twice.” Write the set \(G\). 3. Describe the complement \(\overline{G}\) in words and write its set of outcomes. 4. Find \(P(G)\) and \(P(\overline{G})\), and show that their sum is \(1\).

Hints

- How many choices are available for each digit? Use an organized list or tree diagram. - What is the logical opposite of “at least twice”? - Recall the relationship between the probability of an event and the probability of its complement.

Solution

1. Listing the choices systematically gives \(S = \{111, 112, 121, 122, 211, 212, 221, 222\}\), so \(|S| = 8\). 2. The outcomes containing two or three digits equal to \(1\) are \(G = \{111, 112, 121, 211\}\). 3. The complement means the number contains the digit \(1\) at most once. Therefore, \(\overline{G} = \{122, 212, 221, 222\}\). 4. Each outcome is equally likely, so \(P(G) = \frac{4}{8} = \frac{1}{2} = 0.5\) and \(P(\overline{G}) = \frac{4}{8} = \frac{1}{2} = 0.5\). Their sum is \(0.5 + 0.5 = 1\).

Answer

1. \(S = \{111, 112, 121, 122, 211, 212, 221, 222\}\) 2. \(G = \{111, 112, 121, 211\}\) 3. \(\overline{G}\): The number contains the digit \(1\) at most once. \(\overline{G} = \{122, 212, 221, 222\}\) 4. \(P(G) = 0.5\), \(P(\overline{G}) = 0.5\), and \(0.5 + 0.5 = 1\).
5140827
A two-digit number is formed from the digit cards \(\{1, 2, 3, 4, 5\}\). a) First, each card is replaced after it is drawn, so repeated digits such as \(22\) are possible. Find the probability that the number contains at least one \(5\). b) Now the cards are drawn without replacement. Find the probability that the number contains at least one \(5\). c) Compare the answers. In which case is the probability greater? Briefly explain.

Hints

- Use the complement by counting numbers with no \(5\). - Track how many cards remain on the second draw. - Compare the two probabilities after calculating them.

Solution

1. a) With replacement, there are \(5 \cdot 5 = 25\) two-digit outcomes. There are \(4 \cdot 4 = 16\) outcomes with no \(5\). Therefore, \(P(\text{at least one 5}) = \frac{25 - 16}{25} = \frac{9}{25} = 0.36\). 2. b) Without replacement, there are \(5 \cdot 4 = 20\) outcomes. There are \(4 \cdot 3 = 12\) outcomes with no \(5\). Therefore, \(P(\text{at least one 5}) = \frac{20 - 12}{20} = \frac{2}{5} = 0.4\). 3. c) The probability is greater without replacement. If the first digit is not \(5\), the chance of drawing \(5\) second increases from \(\frac{1}{5}\) to \(\frac{1}{4}\).

Answer

a) \(\frac{9}{25} = 36\%\) b) \(\frac{2}{5} = 40\%\) c) The probability is greater without replacement.
5172077
Three standard six-sided dice are rolled, and the sum is exactly \(7\). List all different combinations of face values when order does not matter. For example, \((4, 2, 1)\) and \((1, 2, 4)\) count as the same combination.

Hints

- Write each combination in the same order, such as greatest to least. - Begin with the greatest possible first value and determine the remaining sum. - Continue systematically so that no combination is missed or counted twice. - Check whether a greatest value of \(2\) could produce a sum of \(7\).

Solution

1. Organize each combination from greatest to least to avoid duplicates. 2. If the greatest value is \(5\), the remaining values must sum to \(2\), giving \((5, 1, 1)\). 3. If the greatest value is \(4\), the remaining values must sum to \(3\), giving \((4, 2, 1)\). 4. If the greatest value is \(3\), the remaining values must sum to \(4\), giving \((3, 3, 1)\) and \((3, 2, 2)\). 5. A greatest value of \(2\) or less cannot work because \(2+2+2=6<7\). Therefore, there are exactly \(4\) combinations.

Answer

\((5, 1, 1)\), \((4, 2, 1)\), \((3, 3, 1)\), and \((3, 2, 2)\)
5172087
A three-digit puzzle code uses digits from \(1\) through \(9\), and digits may repeat. The sum of the three digits is exactly \(6\). How many different codes are possible? Order matters, so \(123\) and \(321\) are different codes.

Hints

- Consider the possible first digits in order. - For each first digit, determine the required sum of the other two digits. - Remember that every digit must be at least \(1\). - Count ordered pairs, since reversing two digits can create a different code.

Solution

1. Organize the codes by their first digit. 2. If the first digit is \(1\), the last two digits must sum to \(5\): \((1, 4)\), \((2, 3)\), \((3, 2)\), and \((4, 1)\). This gives \(4\) codes. 3. If the first digit is \(2\), the last two digits must sum to \(4\), giving \(3\) codes. If the first digit is \(3\), they must sum to \(3\), giving \(2\) codes. If the first digit is \(4\), they must sum to \(2\), giving \(1\) code. 4. A first digit of \(5\) or greater cannot work because each remaining digit is at least \(1\). 5. The total is \(4+3+2+1=10\) codes.

Answer

\(10\) codes
5172097
Three standard six-sided dice are rolled. The product of the three face values is exactly \(12\). List all different combinations of face values when order does not matter.

Hints

- Which die values from \(1\) through \(6\) are factors of \(12\)? - Begin with the greatest possible value and find the required product of the other two. - Check that every product is exactly \(12\). - Write each combination in the same order to avoid duplicates.

Solution

1. Write each combination from greatest to least to avoid duplicates. 2. If the greatest value is \(6\), the other two values must have product \(12\div6=2\), giving \((6, 2, 1)\). 3. If the greatest value is \(4\), the other two values must have product \(12\div4=3\), giving \((4, 3, 1)\). 4. If the greatest value is \(3\), the other two values must have product \(12\div3=4\). The only combination with no value greater than \(3\) is \((3, 2, 2)\). 5. A greatest value of \(2\) cannot work because \(2\cdot2\cdot2=8<12\). Therefore, there are \(3\) combinations.

Answer

\((6, 2, 1)\), \((4, 3, 1)\), and \((3, 2, 2)\)
5172287
How many different ways can you make \(\$0.20\) using dimes, nickels, and pennies? Coin order does not matter. Make an organized list of all possibilities.

Hints

- Begin with the greatest possible number of dimes. - For each number of dimes, determine how the remaining amount can be made with nickels and pennies. - Organize the possibilities in a table so none are missed. - Include the possibility that uses only pennies.

Solution

1. Let each ordered triple \((d, n, p)\) represent the numbers of dimes, nickels, and pennies. 2. With \(2\) dimes, the only possibility is \((2, 0, 0)\). 3. With \(1\) dime, the remaining \(\$0.10\) can be made as \((1, 2, 0)\), \((1, 1, 5)\), or \((1, 0, 10)\). 4. With no dimes, the possibilities are \((0, 4, 0)\), \((0, 3, 5)\), \((0, 2, 10)\), \((0, 1, 15)\), and \((0, 0, 20)\). 5. Altogether, there are \(1+3+5=9\) ways.

Answer

There are \(9\) ways. Using \((d, n, p)\) for dimes, nickels, and pennies, they are \((2, 0, 0)\), \((1, 2, 0)\), \((1, 1, 5)\), \((1, 0, 10)\), \((0, 4, 0)\), \((0, 3, 5)\), \((0, 2, 10)\), \((0, 1, 15)\), and \((0, 0, 20)\).
5172297
How many different ways can you make \(\$0.35\) using quarters, dimes, and nickels? Coin order does not matter. List every combination.

Hints

- Begin with the greatest possible number of quarters. - For each number of quarters, determine how the remaining amount can be made with dimes and nickels. - How many dimes can be used when there are no quarters?

Solution

1. Let each ordered triple \((q, d, n)\) represent the numbers of quarters, dimes, and nickels. 2. With \(1\) quarter, the remaining \(\$0.10\) can be made as \((1, 1, 0)\) or \((1, 0, 2)\). 3. With no quarters, the possibilities are \((0, 3, 1)\), \((0, 2, 3)\), \((0, 1, 5)\), and \((0, 0, 7)\). 4. Therefore, there are \(2+4=6\) combinations.

Answer

There are \(6\) combinations. Using \((q, d, n)\) for quarters, dimes, and nickels, they are \((1, 1, 0)\), \((1, 0, 2)\), \((0, 3, 1)\), \((0, 2, 3)\), \((0, 1, 5)\), and \((0, 0, 7)\).
5233717
A spinner has three equal sections labeled \(1\), \(2\), and \(3\). It is spun three times. a) List the ordered triples in each event: \(A\): A \(1\) occurs only on the first spin. \(B\): The first \(1\) occurs on the third spin. b) Find the number of outcomes in each event: \(C\): The third spin is \(1\). \(D\): The third spin is not \(1\). c) Find \(P(A)\), \(P(B)\), \(P(C)\), and \(P(D)\).

Hints

- Translate each event into conditions on the first, second, and third entries. - “Only on the first spin” excludes \(1\) from the other positions. - “First occurs on the third spin” excludes \(1\) from the first two positions. - Use the fundamental counting principle to count outcomes. - All \(27\) ordered triples are equally likely.

Solution

1. For event \(A\), the first entry is \(1\), and the other entries are \(2\) or \(3\). Thus, \(A=\{(1, 2, 2),(1, 2, 3),(1, 3, 2),(1, 3, 3)\}\). 2. For event \(B\), the first two entries are \(2\) or \(3\), and the third entry is \(1\). Thus, \(B=\{(2, 2, 1),(2, 3, 1),(3, 2, 1),(3, 3, 1)\}\). 3. In event \(C\), the first two spins each have \(3\) choices and the third is fixed, so there are \(3\cdot 3=9\) outcomes. In event \(D\), the third spin has \(2\) choices, so there are \(3\cdot 3\cdot 2=18\) outcomes. 4. There are \(3^3=27\) equally likely outcomes. Therefore, \(P(A)=\frac{4}{27}\), \(P(B)=\frac{4}{27}\), \(P(C)=\frac{9}{27}=\frac{1}{3}\), and \(P(D)=\frac{18}{27}=\frac{2}{3}\).

Answer

a) \(A=\{(1, 2, 2),(1, 2, 3),(1, 3, 2),(1, 3, 3)\}\); \(B=\{(2, 2, 1),(2, 3, 1),(3, 2, 1),(3, 3, 1)\}\) b) \(C\): \(9\) outcomes; \(D\): \(18\) outcomes c) \(P(A)=\frac{4}{27}\); \(P(B)=\frac{4}{27}\); \(P(C)=\frac{1}{3}\); \(P(D)=\frac{2}{3}\)
5238047
An urn contains four balls labeled \(1\), \(2\), \(3\), and \(4\). Two draws are made with replacement. Find the probability that: a) The sum of the two numbers is exactly \(5\). b) The product of the two numbers is a perfect square. c) The first number is greater than the second number.

Hints

- Use the fundamental counting principle to find the total number of ordered pairs. - Make a table or list of all \(16\) outcomes. - Include equal factors such as \(2\cdot 2\) when checking perfect-square products. - List ordered pairs systematically.

Solution

1. There are \(4\cdot 4=16\) equally likely ordered outcomes. 2. The outcomes with sum \(5\) are \((1, 4)\), \((2, 3)\), \((3, 2)\), and \((4, 1)\). Thus, the probability is \(\frac{4}{16}=\frac{1}{4}\). 3. The outcomes with a perfect-square product are \((1, 1)\), \((1, 4)\), \((2, 2)\), \((3, 3)\), \((4, 1)\), and \((4, 4)\). Thus, the probability is \(\frac{6}{16}=\frac{3}{8}\). 4. The outcomes with the first number greater are \((2, 1)\), \((3, 1)\), \((3, 2)\), \((4, 1)\), \((4, 2)\), and \((4, 3)\). Thus, the probability is \(\frac{6}{16}=\frac{3}{8}\).

Answer

a) \(\frac{1}{4}=0.25\) b) \(\frac{3}{8}=0.375\) c) \(\frac{3}{8}=0.375\)
5309607
Two fair six-sided dice are rolled, and their sum \(S\) is recorded. a) Find the probability that \(S\le 4\) or \(S\ge 10\). b) Let \(E\) be the event \(3<S<11\). Find the probability of \(E^c\).

Hints

- List the number of ordered outcomes that produce each possible sum. - Translate “greater than \(3\) and less than \(11\)” into an inequality. - The endpoints are included in “at most” and “at least.” - An event and its complement have probabilities that add to \(1\).

Solution

1. The \(6\times 6\) sample space has \(36\) equally likely ordered outcomes. 2. For \(S\le 4\), the numbers of outcomes for sums \(2\), \(3\), and \(4\) are \(1\), \(2\), and \(3\), for a total of \(6\). For \(S\ge 10\), the counts for sums \(10\), \(11\), and \(12\) are \(3\), \(2\), and \(1\), also totaling \(6\). The two events are disjoint, so the probability is \(\frac{12}{36}=\frac{1}{3}\). 3. The complement of \(3<S<11\) is \(S\le 3\) or \(S\ge 11\). These sums have \(1+2+2+1=6\) outcomes, so \(P(E^c)=\frac{6}{36}=\frac{1}{6}\).

Answer

a) \(\frac{1}{3}\) b) \(P(E^c)=\frac{1}{6}\)
5319957
Spinner A has five equal sections: red \(1\), red \(2\), blue \(3\), blue \(4\), and yellow \(5\). Spinner B has four equal sections: red \(1\), blue \(2\), blue \(3\), and green \(4\). Each spinner is spun once. Find the probability that: a) Both spinners land on the same color. b) The sum of the two numbers is at least \(6\). Give each probability as a simplified fraction and a percent.
Figure for problem 531995

Hints

- Use the fundamental counting principle to find the total number of section pairs. - Count the colors that appear on both spinners. - List the ordered number pairs with sum at least \(6\). - Divide favorable equally likely outcomes by all outcomes.

Solution

1. Spinner A has \(5\) sections and spinner B has \(4\) sections, so there are \(5\cdot 4=20\) equally likely section pairs. 2. For matching colors, there are \(2\cdot 1=2\) red-red pairs and \(2\cdot 2=4\) blue-blue pairs. Thus, \(P(\text{same color})=\frac{6}{20}=\frac{3}{10}=30\%\). 3. The number pairs with sum at least \(6\) are \((2, 4)\), \((3, 3)\), \((3, 4)\), \((4, 2)\), \((4, 3)\), \((4, 4)\), \((5, 1)\), \((5, 2)\), \((5, 3)\), and \((5, 4)\). Therefore, \(P(\text{sum}\ge 6)=\frac{10}{20}=\frac{1}{2}=50\%\).

Answer

a) \(\frac{3}{10}=30\%\) b) \(\frac{1}{2}=50\%\)
5320057
A spinner has six equal sections: red \(1\), blue \(2\), yellow \(3\), red \(2\), blue \(1\), and yellow \(2\). It is spun twice. Find the probability that: a) The same number occurs on both spins. b) The sum of the two numbers is greater than \(4\). c) The first spin lands on red and the second spin lands on blue.
Figure for problem 532005

Hints

- Count how many sections carry each number and each color. - Treat the two spins as ordered. - For part a, add the probabilities for matching \(1\)s, matching \(2\)s, and matching \(3\)s. - For part b, identify the possible number pairs before counting section pairs.

Solution

1. There are \(6\cdot 6=36\) equally likely section pairs. 2. The number \(1\) appears on \(2\) sections, \(2\) appears on \(3\) sections, and \(3\) appears on \(1\) section. Thus, \(P(\text{same number})=\frac{2^2+3^2+1^2}{36}=\frac{14}{36}=\frac{7}{18}\). 3. A sum greater than \(4\) comes from number pairs \((2, 3)\), \((3, 2)\), or \((3, 3)\). These represent \(3\cdot 1+1\cdot 3+1\cdot 1=7\) section pairs, so the probability is \(\frac{7}{36}\). 4. There are \(2\) red sections and \(2\) blue sections. Therefore, \(P(\text{red then blue})=\frac{2}{6}\cdot\frac{2}{6}=\frac{1}{9}\).

Answer

a) \(\frac{7}{18}\approx 38.9\%\) b) \(\frac{7}{36}\approx 19.4\%\) c) \(\frac{1}{9}\approx 11.1\%\)
5320127
Spinner A has four equal sections: red \(1\), blue \(2\), green \(3\), and yellow \(4\). Spinner B has six equal sections: red \(1\), blue \(2\), red \(3\), yellow \(4\), red \(5\), and blue \(6\). Each spinner is spun once. Find each probability as a simplified fraction. a) Both spinners land on red sections. b) The sum of the two numbers is exactly \(6\).
Figure for problem 532012

Hints

- Count all ordered section pairs. - For part a, multiply the red probabilities from the two spinners. - For part b, list all ordered number pairs with sum \(6\). - Simplify each fraction.

Solution

1. Spinner A has \(4\) sections and spinner B has \(6\) sections, so there are \(4\cdot 6=24\) equally likely section pairs. 2. Spinner A has \(1\) red section, and spinner B has \(3\) red sections. Therefore, \(P(\text{both red})=\frac{1}{4}\cdot\frac{3}{6}=\frac{1}{8}\). 3. The number pairs with sum \(6\) are \((1, 5)\), \((2, 4)\), \((3, 3)\), and \((4, 2)\). Thus, \(P(\text{sum}=6)=\frac{4}{24}=\frac{1}{6}\).

Answer

a) \(\frac{1}{8}\) b) \(\frac{1}{6}\)
5320427
A spinner has six equal sections labeled and colored as shown. It is spun twice. Find the probability that the sum of the two numbers is at least \(6\). Give the answer as a simplified fraction.
Figure for problem 532042

Hints

- Count how many sections carry each number. - List the ordered number pairs with sum at least \(6\). - Account for repeated labels by counting section pairs. - Simplify the final fraction.

Solution

1. The possible numbers and their probabilities are \(P(1)=\frac{1}{6}\), \(P(2)=\frac{1}{6}\), \(P(3)=\frac{2}{6}\), and \(P(5)=\frac{2}{6}\). 2. The number pairs with sum at least \(6\) are \((1, 5)\), \((2, 5)\), \((3, 3)\), \((3, 5)\), \((5, 1)\), \((5, 2)\), \((5, 3)\), and \((5, 5)\). 3. Counting the corresponding section pairs gives \(2+2+4+4+2+2+4+4=24\) favorable outcomes out of \(36\). 4. Therefore, the probability is \(\frac{24}{36}=\frac{2}{3}\).

Answer

\(\frac{2}{3}\)
5320537
A spinner has eight equal sections: three red, four blue, and one green. It is spun twice. Find each probability as a simplified fraction and a percent. a) Both spins are the same color. b) Green occurs at least once. c) The first spin is red and the second spin is blue.
Figure for problem 532053

Hints

- Find the one-spin probability of each color. - Add the three matching-color path probabilities. - For at least one green, use the complement of no green. - For a specified order, multiply the two probabilities.

Solution

1. The one-spin probabilities are \(P(\text{red})=\frac{3}{8}\), \(P(\text{blue})=\frac{4}{8}\), and \(P(\text{green})=\frac{1}{8}\). 2. \(P(\text{same color})=\left(\frac{3}{8}\right)^2+\left(\frac{4}{8}\right)^2+\left(\frac{1}{8}\right)^2=\frac{26}{64}=\frac{13}{32}=40.625\%\). 3. Use the complement of no green: \(P(\text{at least one green})=1-\left(\frac{7}{8}\right)^2=\frac{15}{64}=23.4375\%\). 4. \(P(\text{red then blue})=\frac{3}{8}\cdot\frac{4}{8}=\frac{3}{16}=18.75\%\).

Answer

a) \(\frac{13}{32}=40.625\%\) b) \(\frac{15}{64}=23.4375\%\) c) \(\frac{3}{16}=18.75\%\)
5320887
A spinner has five equal sections: two green, two red, and one yellow. It is spun twice. Find each probability as a simplified fraction and a percent. a) The first spin is green and the second spin is yellow. b) Red occurs at least once.
Figure for problem 532088

Hints

- Count the sections of each color. - Multiply the probabilities for the specified order in part a. - For part b, use the complement of landing on no red sections.

Solution

1. The one-spin probabilities are \(P(\text{green})=\frac{2}{5}\), \(P(\text{red})=\frac{2}{5}\), and \(P(\text{yellow})=\frac{1}{5}\). 2. \(P(\text{green then yellow})=\frac{2}{5}\cdot\frac{1}{5}=\frac{2}{25}=8\%\). 3. The probability of not landing on red is \(\frac{3}{5}\). Therefore, \(P(\text{at least one red})=1-\left(\frac{3}{5}\right)^2=\frac{16}{25}=64\%\).

Answer

a) \(\frac{2}{25}=8\%\) b) \(\frac{16}{25}=64\%\)
5320957
Lara spins an eight-section spinner with \(2\) red sections, \(4\) blue sections, and \(2\) green sections twice. Find the probability that the spinner lands on red at least once. Give the answer as a simplified fraction and a percent.
Figure for problem 532095

Hints

- Count the red sections. - State the complement of at least one red. - Multiply the not-red probability for two spins, then subtract from \(1\).

Solution

1. Two of the eight sections are red, so \(P(\text{red})=\frac{2}{8}=\frac{1}{4}\) and \(P(\text{not red})=\frac{3}{4}\). 2. The probability of no red on either spin is \(\left(\frac{3}{4}\right)^2=\frac{9}{16}\). 3. Therefore, \(P(\text{at least one red})=1-\frac{9}{16}=\frac{7}{16}=43.75\%\).

Answer

\(\frac{7}{16}=43.75\%\)
5321277
A spinner has eight equal sections: \(4\) red, \(2\) green, and \(2\) yellow. It is spun twice. Find the probability that: a) Both spins are the same color. b) Yellow occurs at least once.
Figure for problem 532127

Hints

- Find the probability of each color on one spin. - Add the probabilities of the matching-color paths. - For part b, use the complement of no yellow.

Solution

1. The one-spin probabilities are \(P(\text{red})=\frac{4}{8}=\frac{1}{2}\), \(P(\text{green})=\frac{2}{8}=\frac{1}{4}\), and \(P(\text{yellow})=\frac{2}{8}=\frac{1}{4}\). 2. \(P(\text{same color})=\left(\frac{1}{2}\right)^2+\left(\frac{1}{4}\right)^2+\left(\frac{1}{4}\right)^2=\frac{3}{8}=37.5\%\). 3. The probability of no yellow on one spin is \(\frac{3}{4}\). Therefore, \(P(\text{at least one yellow})=1-\left(\frac{3}{4}\right)^2=\frac{7}{16}=43.75\%\).

Answer

a) \(\frac{3}{8}=37.5\%\) b) \(\frac{7}{16}=43.75\%\)
5321427
A spinner has five equal sections: - a red section labeled \(1\) - a blue section labeled \(2\) - a red section labeled \(3\) - a green section labeled \(4\) - a blue section labeled \(5\) The spinner is spun twice. a) Find the probability that the sum of the two numbers is at least \(7\). b) Find the probability that the two spins land on different colors.
Figure for problem 532142

Hints

- Determine the total number of ordered outcomes for two spins. - Organize the number pairs systematically. - For part a, identify which pairs have sums that meet the condition. - For part b, consider counting the complement: two spins of the same color.

Solution

1. There are \(5\cdot 5=25\) equally likely ordered outcomes. 2. The outcomes with a sum of at least \(7\) are \((2, 5)\), \((3, 4)\), \((3, 5)\), \((4, 3)\), \((4, 4)\), \((4, 5)\), \((5, 2)\), \((5, 3)\), \((5, 4)\), and \((5, 5)\). Therefore, \(P(\text{sum}\ge 7)=\frac{10}{25}=\frac{2}{5}=0.40\). 3. For the complement in part b, there are \(2\cdot 2=4\) red-red outcomes, \(2\cdot 2=4\) blue-blue outcomes, and \(1\) green-green outcome. Thus, \(P(\text{same color})=\frac{9}{25}\). 4. Therefore, \(P(\text{different colors})=1-\frac{9}{25}=\frac{16}{25}=0.64\).

Answer

a) \(\frac{2}{5}\), or \(40\%\) b) \(\frac{16}{25}\), or \(64\%\)
5321467
The spinner shown has six equal sections and is spun twice. Find the probability of each event. a) Both spins land on the same color. b) The spinner lands on red at least once. c) The first spin is green and the second spin is blue.
Figure for problem 532146

Hints

- Find the probability of each color on one spin. - For part a, add the probabilities of the three matching-color outcomes. - For part b, use the complement of no red. - For part c, multiply the probabilities in the stated order. - Simplify each fraction.

Solution

1. The one-spin probabilities are \(P(\text{green})=\frac{3}{6}=\frac{1}{2}\), \(P(\text{blue})=\frac{2}{6}=\frac{1}{3}\), and \(P(\text{red})=\frac{1}{6}\). 2. The matching-color outcomes are green-green, blue-blue, and red-red: \(P(\text{same color})=\left(\frac{1}{2}\right)^2+\left(\frac{1}{3}\right)^2+\left(\frac{1}{6}\right)^2=\frac{1}{4}+\frac{1}{9}+\frac{1}{36}=\frac{7}{18}\). 3. Use the complement of no red: \(P(\text{at least one red})=1-\left(\frac{5}{6}\right)^2=1-\frac{25}{36}=\frac{11}{36}\). 4. For the specified order, multiply the probabilities: \(P(\text{green then blue})=\frac{1}{2}\cdot\frac{1}{3}=\frac{1}{6}\).

Answer

a) \(\frac{7}{18}\) b) \(\frac{11}{36}\) c) \(\frac{1}{6}\)
5321497
Spinner A has three equal sections labeled \(1\), \(2\), and \(3\). Spinner B has four equal sections labeled \(1\), \(2\), \(3\), and \(4\). Each spinner is spun once. Find the probability of each event. a) The sum of the two numbers is \(5\). b) The number on spinner B is greater than the number on spinner A. c) Both spinners show the same number.
Figure for problem 532149

Hints

- Determine how many ordered pairs are possible. - List the ordered pairs that satisfy each condition. - Divide the number of favorable pairs by the total number of equally likely pairs. - Simplify each fraction.

Solution

1. There are \(3\cdot 4=12\) equally likely ordered pairs \((a, b)\), where \(a\) is the result from spinner A and \(b\) is the result from spinner B. Each pair has probability \(\frac{1}{12}\). 2. The pairs with sum \(5\) are \((1, 4)\), \((2, 3)\), and \((3, 2)\). Therefore, \(P(\text{sum }5)=\frac{3}{12}=\frac{1}{4}\). 3. The pairs with \(b>a\) are \((1, 2)\), \((1, 3)\), \((1, 4)\), \((2, 3)\), \((2, 4)\), and \((3, 4)\). Therefore, \(P(b>a)=\frac{6}{12}=\frac{1}{2}\). 4. The matching pairs are \((1, 1)\), \((2, 2)\), and \((3, 3)\). Therefore, \(P(\text{same number})=\frac{3}{12}=\frac{1}{4}\).

Answer

a) \(\frac{1}{4}\) b) \(\frac{1}{2}\) c) \(\frac{1}{4}\)
5321527
A spinner has four equal sections: three blue and one yellow. It is spun three times. Event \(E\) is “exactly one spin lands on yellow.” a) List all outcomes in event \(E\). Use B for blue and Y for yellow. b) Find \(P(E)\) as a simplified fraction.
Figure for problem 532152

Hints

- Decide which one of the three positions can contain yellow. - Find the one-spin probabilities of blue and yellow. - Multiply along each favorable outcome. - Add the probabilities of the favorable outcomes.

Solution

1. Exactly one yellow can occur in the first, second, or third position. The outcomes are \((Y, B, B)\), \((B, Y, B)\), and \((B, B, Y)\). 2. The one-spin probabilities are \(P(Y)=\frac{1}{4}\) and \(P(B)=\frac{3}{4}\). 3. Each favorable outcome has probability \(\frac{1}{4}\cdot\frac{3}{4}\cdot\frac{3}{4}=\frac{9}{64}\). 4. Add the three equal probabilities: \(P(E)=3\cdot\frac{9}{64}=\frac{27}{64}\).

Answer

a) \((Y, B, B)\), \((B, Y, B)\), and \((B, B, Y)\) b) \(P(E)=\frac{27}{64}\)
5321617
The spinner shown has eight equal sections labeled \(1\) through \(8\). Sections \(1\) through \(4\) are blue, sections \(5\) and \(6\) are green, and sections \(7\) and \(8\) are red. The spinner is spun twice. Let the events be: A: Both numbers are odd. B: The sum of the two numbers is greater than \(12\). C: The first spin is blue and the second spin is red. Find each probability. a) \(P(C)\) b) \(P(A)\) c) \(P(B)\)
Figure for problem 532161

Hints

- Each numbered section has the same probability. - For part a, multiply the probability of blue by the probability of red. - For part b, count the odd numbers on the spinner. - For part c, list ordered pairs systematically whose sum is greater than \(12\).

Solution

1. Four of the eight sections are blue and two are red. Therefore, \(P(C)=\frac{4}{8}\cdot\frac{2}{8}=\frac{1}{8}\). 2. Four of the eight numbers are odd. Therefore, \(P(A)=\frac{4}{8}\cdot\frac{4}{8}=\frac{1}{4}\). 3. There are \(8\cdot 8=64\) equally likely ordered pairs. The pairs whose sum is greater than \(12\) are \((5, 8)\), \((6, 7)\), \((6, 8)\), \((7, 6)\), \((7, 7)\), \((7, 8)\), \((8, 5)\), \((8, 6)\), \((8, 7)\), and \((8, 8)\). Thus, \(P(B)=\frac{10}{64}=\frac{5}{32}\).

Answer

a) \(P(C)=\frac{1}{8}\) b) \(P(A)=\frac{1}{4}\) c) \(P(B)=\frac{5}{32}\)
5358937
The spinner shown is spun twice. It has two blue sections labeled \(1\) and \(2\), two red sections labeled \(3\) and \(4\), two green sections labeled \(1\) and \(2\), and two yellow sections labeled \(3\) and \(4\). Find the probability of each event. a) The same number is spun both times. b) The sum of the two numbers is exactly \(4\). c) The two sections have different colors. d) The number \(1\) is spun at least once.
Figure for problem 535893

Hints

- Determine the number of equally likely ordered pairs of sections. - Count how many section pairs satisfy each required number or color condition. - Remember that each number and each color appears more than once. - For parts c and d, it may be easier to count the complementary outcomes first.

Solution

1. The spinner has \(8\) equal sections, so two spins produce \(8 \cdot 8 = 64\) equally likely ordered pairs of sections. 2. Each of the four numbers appears on two sections. For each number, there are \(2 \cdot 2 = 4\) ordered pairs showing that number twice. Thus, part a has \(4 \cdot 4 = 16\) favorable outcomes, and the probability is \(\frac{16}{64} = \frac{1}{4}\). 3. A sum of \(4\) can come from the number pairs \((1, 3)\), \((2, 2)\), and \((3, 1)\). Each number pair corresponds to \(2 \cdot 2 = 4\) section pairs, so there are \(3 \cdot 4 = 12\) favorable outcomes. The probability is \(\frac{12}{64} = \frac{3}{16}\). 4. For each of the four colors, there are \(2 \cdot 2 = 4\) ordered pairs with that same color, so there are \(16\) same-color outcomes. Therefore, \(64 - 16 = 48\) outcomes have different colors, giving \(\frac{48}{64} = \frac{3}{4}\). 5. Six sections are not labeled \(1\). Therefore, \(6 \cdot 6 = 36\) ordered pairs contain no \(1\), so \(64 - 36 = 28\) contain at least one \(1\). The probability is \(\frac{28}{64} = \frac{7}{16}\).

Answer

a) \(\frac{1}{4} = 25\%\) b) \(\frac{3}{16} = 18.75\%\) c) \(\frac{3}{4} = 75\%\) d) \(\frac{7}{16} = 43.75\%\)
5359857
At a carnival booth, a spinner with ten equal sections—five blue, three red, and two green—is spun twice. a) Find the probability that both spins land on green. Give the answer as a percent. b) Find the probability that red occurs at least once.
Figure for problem 535985

Hints

- Count the sections of each color. - Multiply the green probability for two spins in part a. - For part b, use the complement of no red.

Solution

1. The spinner has ten equal sections: five blue, three red, and two green. Therefore, \(P(\text{green})=\frac{2}{10}=\frac{1}{5}\) and \(P(\text{red})=\frac{3}{10}\). 2. \(P(\text{green twice})=\frac{1}{5}\cdot\frac{1}{5}=\frac{1}{25}=4\%\). 3. Use the complement of no red. The probability of not red on one spin is \(\frac{7}{10}\), so \(P(\text{at least one red})=1-\left(\frac{7}{10}\right)^2=1-\frac{49}{100}=\frac{51}{100}=51\%\).

Answer

a) \(4\%\) b) \(\frac{51}{100}=51\%\)
5359867
A spinner has eight equal sections: four red, two blue, and two yellow. It is spun three times. a) Find the probability of event \(E_1\): no spin lands on yellow. b) Find the probability of event \(E_2\): exactly two spins land on red. c) Which event is more likely? Justify your answer by comparing the probabilities.
Figure for problem 535986

Hints

- Find the probability of each color on one spin. - For part a, multiply the probability of not yellow for all three spins. - For part b, list the three possible positions of the spin that is not red. - Rewrite the fractions with a common denominator to compare them.

Solution

1. The one-spin probabilities are \(P(\text{red})=\frac{1}{2}\), \(P(\text{blue})=\frac{1}{4}\), and \(P(\text{yellow})=\frac{1}{4}\). 2. The probability of not yellow on one spin is \(\frac{3}{4}\). Therefore, \(P(E_1)=\left(\frac{3}{4}\right)^3=\frac{27}{64}\). 3. Exactly two red spins can occur in three orders. Since both red and not red have probability \(\frac{1}{2}\), \(P(E_2)=3\cdot\left(\frac{1}{2}\right)^2\cdot\frac{1}{2}=\frac{3}{8}=\frac{24}{64}\). 4. Since \(\frac{27}{64}>\frac{24}{64}\), event \(E_1\) is more likely.

Answer

a) \(P(E_1)=\frac{27}{64}\) b) \(P(E_2)=\frac{3}{8}\) c) Event \(E_1\) is more likely because \(\frac{27}{64}>\frac{24}{64}\).
5359877
The spinner shown has five equal sections and is spun twice. The two numbers are added. Find the probability that the sum is exactly \(4\).
Figure for problem 535987

Hints

- Find the probability of each number on one spin. - List the ordered pairs whose sum is \(4\). - Multiply within each ordered pair and add the favorable probabilities.

Solution

1. The number \(1\) appears once, \(2\) appears twice, \(3\) appears once, and \(4\) appears once. Thus, \(P(1)=\frac{1}{5}\), \(P(2)=\frac{2}{5}\), and \(P(3)=\frac{1}{5}\). 2. The ordered pairs with sum \(4\) are \((1, 3)\), \((3, 1)\), and \((2, 2)\). 3. Their probabilities are \(\frac{1}{5}\cdot\frac{1}{5}=\frac{1}{25}\), \(\frac{1}{5}\cdot\frac{1}{5}=\frac{1}{25}\), and \(\frac{2}{5}\cdot\frac{2}{5}=\frac{4}{25}\). 4. Therefore, \(P(\text{sum }4)=\frac{1}{25}+\frac{1}{25}+\frac{4}{25}=\frac{6}{25}=24\%\).

Answer

\(\frac{6}{25}=24\%\)
5360227
A spinner has eight equal sections: three green, four yellow, and one orange. It is spun three times. Find the probability of each event. a) Exactly two spins land on yellow. b) Orange occurs at least once. c) The colors occur in the exact order green, yellow, orange. d) Yellow occurs at most once.
Figure for problem 536022

Hints

- Find the probability of each color on one spin. - For “exactly,” count the possible positions of the specified color. - For “at least once,” consider using a complement. - For an exact order, multiply the probabilities in that order. - “At most once” includes zero times and one time.

Solution

1. The one-spin probabilities are \(P(\text{green})=\frac{3}{8}\), \(P(\text{yellow})=\frac{1}{2}\), and \(P(\text{orange})=\frac{1}{8}\). 2. Exactly two yellow spins can occur in three orders. Since the probability of not yellow is also \(\frac{1}{2}\), \(P(\text{exactly two yellow})=3\cdot\left(\frac{1}{2}\right)^2\cdot\frac{1}{2}=\frac{3}{8}\). 3. Use the complement of no orange: \(P(\text{at least one orange})=1-\left(\frac{7}{8}\right)^3=\frac{169}{512}\). 4. For the specified order, \(P(\text{green, yellow, orange})=\frac{3}{8}\cdot\frac{1}{2}\cdot\frac{1}{8}=\frac{3}{128}\). 5. At most one yellow means zero or one yellow. The probabilities are \(P(\text{zero yellow})=\left(\frac{1}{2}\right)^3=\frac{1}{8}\) and \(P(\text{exactly one yellow})=3\cdot\frac{1}{2}\cdot\left(\frac{1}{2}\right)^2=\frac{3}{8}\). Therefore, \(P(\text{at most one yellow})=\frac{1}{8}+\frac{3}{8}=\frac{1}{2}\).

Answer

a) \(\frac{3}{8}\) b) \(\frac{169}{512}\) c) \(\frac{3}{128}\) d) \(\frac{1}{2}\)
5360617
A spinner has eight equal sections labeled \(1\) through \(8\). It is spun three times, and each number is recorded. Find the probability of each event. a) Only the first and third numbers are even. b) Only the first number is a perfect square. c) All three numbers are greater than \(5\). d) The same number occurs on all three spins.
Figure for problem 536061

Hints

- For each part, determine which numbers are allowed on each spin. - “Only” means the other spins must not have the named property. - List the perfect squares from \(1\) through \(8\). - Multiply probabilities along a specified sequence. - For part d, count the possible repeated-number outcomes.

Solution

1. There are four even numbers and four odd numbers from \(1\) through \(8\). Therefore, \(P(\text{even, odd, even})=\frac{4}{8}\cdot\frac{4}{8}\cdot\frac{4}{8}=\frac{1}{8}\). 2. The perfect squares are \(1\) and \(4\), so the probability of a perfect square is \(\frac{2}{8}=\frac{1}{4}\), and the probability of not getting a perfect square is \(\frac{6}{8}=\frac{3}{4}\). Thus, \(P(\text{square, not square, not square})=\frac{1}{4}\cdot\frac{3}{4}\cdot\frac{3}{4}=\frac{9}{64}\). 3. The numbers greater than \(5\) are \(6\), \(7\), and \(8\). Therefore, \(P(\text{all greater than }5)=\left(\frac{3}{8}\right)^3=\frac{27}{512}\). 4. The matching outcomes are \((1, 1, 1)\), \((2, 2, 2)\), through \((8, 8, 8)\). There are eight such outcomes, each with probability \(\left(\frac{1}{8}\right)^3\). Therefore, \(P(\text{same number three times})=8\cdot\left(\frac{1}{8}\right)^3=\frac{1}{64}\).

Answer

a) \(\frac{1}{8}\) b) \(\frac{9}{64}\) c) \(\frac{27}{512}\) d) \(\frac{1}{64}\)
5360757
The spinner shown has eight equal sections: two blue, three red, and one each green, yellow, and orange. It is spun twice. Find the probability of each event. a) The sum of the two numbers is \(3\). b) The first number is \(1\), and the second number is greater than \(1\). c) Both spins land on the same color.
Figure for problem 536075

Hints

- Find the probability of each number and each color on one spin. - For part a, list the ordered pairs whose sum is \(3\). - For part b, count the sections labeled with a number greater than \(1\). - For part c, add the probabilities of blue-blue, red-red, and the three other matching-color outcomes.

Solution

1. The number probabilities are \(P(1)=\frac{2}{8}=\frac{1}{4}\), \(P(2)=\frac{3}{8}\), and \(P(3)=P(4)=P(5)=\frac{1}{8}\). 2. A sum of \(3\) occurs with \((1, 2)\) or \((2, 1)\). Therefore, \(P(\text{sum }3)=\frac{2}{8}\cdot\frac{3}{8}+\frac{3}{8}\cdot\frac{2}{8}=\frac{3}{16}\). 3. The probability that the first number is \(1\) is \(\frac{2}{8}\). Six of the eight sections have numbers greater than \(1\). Thus, \(P(\text{first }1\text{, second greater than }1)=\frac{2}{8}\cdot\frac{6}{8}=\frac{3}{16}\). 4. Blue appears on two sections, red on three sections, and green, yellow, and orange each on one section. Therefore, \(P(\text{same color})=\left(\frac{2}{8}\right)^2+\left(\frac{3}{8}\right)^2+3\cdot\left(\frac{1}{8}\right)^2=\frac{1}{4}\).

Answer

a) \(\frac{3}{16}\) b) \(\frac{3}{16}\) c) \(\frac{1}{4}\)
5360857
A spinner has ten equal sections: five blue, three red, and two yellow. a) Find the probability of blue, red, and yellow on one spin. b) The spinner is spun twice. Find the probability that both spins land on the same color. c) A student claims, “The probability of getting yellow at least once in two spins is greater than \(35\%\).” Is the student correct? Show your calculation.
Figure for problem 536085

Hints

- Count the sections of each color. - For part b, add the probabilities of the three matching-color outcomes. - For part c, use the complement of no yellow. - Compare the resulting percent with \(35\%\).

Solution

1. The one-spin probabilities are \(P(\text{blue})=\frac{5}{10}=\frac{1}{2}\), \(P(\text{red})=\frac{3}{10}\), and \(P(\text{yellow})=\frac{2}{10}=\frac{1}{5}\). 2. The matching-color outcomes are blue-blue, red-red, and yellow-yellow. Therefore, \(P(\text{same color})=\left(\frac{1}{2}\right)^2+\left(\frac{3}{10}\right)^2+\left(\frac{1}{5}\right)^2=\frac{19}{50}=38\%\). 3. Use the complement of no yellow. The probability of not yellow on one spin is \(\frac{4}{5}\), so \(P(\text{at least one yellow})=1-\left(\frac{4}{5}\right)^2=\frac{9}{25}=36\%\). Since \(36\%>35\%\), the student is correct.

Answer

a) \(P(\text{blue})=\frac{1}{2}\), \(P(\text{red})=\frac{3}{10}\), and \(P(\text{yellow})=\frac{1}{5}\) b) \(\frac{19}{50}=38\%\) c) Yes. The probability is \(\frac{9}{25}=36\%\), which is greater than \(35\%\).
5360887
A spinner is divided into five equal sections labeled \(1\) through \(5\). The spinner is spun twice. Compare these events: Event \(A\): The sum of the two numbers is exactly \(6\). Event \(B\): The first number is greater than the second number. Which event is more likely? Support your answer by calculating both probabilities.
Figure for problem 536088

Hints

- Make a table of all \(25\) ordered pairs. - Mark the pairs with a sum of \(6\). - Mark the pairs in which the first number is greater. - For equally likely outcomes, divide favorable outcomes by total outcomes.

Solution

1. There are \(5\cdot 5=25\) equally likely ordered outcomes. 2. Event \(A\) contains \((1, 5)\), \((2, 4)\), \((3, 3)\), \((4, 2)\), and \((5, 1)\). Therefore, \(P(A)=\frac{5}{25}=\frac{1}{5}=0.20\). 3. Event \(B\) contains \((2, 1)\), \((3, 1)\), \((3, 2)\), \((4, 1)\), \((4, 2)\), \((4, 3)\), \((5, 1)\), \((5, 2)\), \((5, 3)\), and \((5, 4)\). Therefore, \(P(B)=\frac{10}{25}=\frac{2}{5}=0.40\). 4. Since \(0.40>0.20\), event \(B\) is more likely.

Answer

Event \(B\) is more likely. \(P(A)=\frac{1}{5}=20\%\), and \(P(B)=\frac{2}{5}=40\%\).
5374627
A basketball player takes three free throws and wants to make exactly two shots. The tree diagram shows the running total of made shots after each attempt. Let \(M\) represent a make and \(X\) represent a miss. a) How many paths result in exactly two makes? Name the paths. b) What running totals after the second shot still allow the player to finish with exactly two makes? c) For each total from part b, state what must happen on the third shot.
Figure for problem 537462

Hints

- Find all final nodes labeled “2 makes.” - Trace those paths backward to the totals after the second shot. - If the player already has two makes, determine what the last result must be. - If the player has only one make, determine what the last result must be.

Solution

1. The paths with exactly two makes are \(MMX\), \(MXM\), and \(XMM\). There are \(3\) paths. 2. After the second shot, the player must have either \(1\) make or \(2\) makes. 3. With \(1\) make after two shots, the third shot must be made. With \(2\) makes after two shots, the third shot must be missed. With \(0\) makes after two shots, the goal is no longer possible.

Answer

a) \(3\) paths: \(MMX\), \(MXM\), and \(XMM\) b) \(1\) make or \(2\) makes c) From \(1\) make, the third shot must be made; from \(2\) makes, the third shot must be missed.
5375237
A fair four-sided die labeled \(1\) through \(4\) is rolled twice. Find the probability that the second number is greater than the first number.
Figure for problem 537523

Hints

- For each possible first number, list the larger second numbers. - Compare the favorable endpoints with all \(16\) endpoints.

Solution

1. The favorable ordered pairs are \((1, 2)\), \((1, 3)\), \((1, 4)\), \((2, 3)\), \((2, 4)\), and \((3, 4)\). 2. There are \(6\) favorable outcomes among \(4 \cdot 4 = 16\) equally likely ordered outcomes. 3. Therefore, \(P = \frac{6}{16} = \frac{3}{8}\).

Answer

\(\frac{3}{8} = 37.5\%\)
5199007
A three-digit code uses only the digits \(1,2,3,\) and \(4\). a) Use an organized list to find all codes whose digits have a sum of exactly \(5\). How many are there? b) How many codes begin with \(1\) and contain exactly one pair of equal adjacent digits? The code \(112\) qualifies, but \(111\) does not.

Hints

- For part a, first write \(5\) as a sum of three allowed positive digits. - Then arrange each resulting group of digits in every distinct order. - For part b, separate the cases in which the equal pair is first or last. - Exclude \(111\), which creates two overlapping equal adjacent pairs. - List the qualifying codes to verify the count.

Solution

1. Ignoring order at first, the only three allowed digits with sum \(5\) are \(1, 1, 3\) and \(1, 2, 2\). 2. Their distinct arrangements are \(113,131,311,122,212,\) and \(221\), giving \(6\) codes. 3. For part b, one case has equal first and second digits: \(11y\), where \(y\) can be \(2,3,\) or \(4\). This gives \(112,113,\) and \(114\). 4. The other case has equal second and third digits: \(1xx\), where \(x\) can be \(2,3,\) or \(4\). This gives \(122,133,\) and \(144\). 5. The two cases are disjoint, so there are \(3+3=6\) codes.

Answer

a) \(6\) codes: \(113,131,311,122,212,221\) b) \(6\) codes: \(112,113,114,122,133,144\)
5211557
You have a balance scale and three weights with masses \(1\,\text{kg}\), \(2\,\text{kg}\), and \(5\,\text{kg}\). Weights may be placed on either pan. For example, placing the \(5\,\text{kg}\) weight opposite the object and the \(1\,\text{kg}\) weight beside the object measures \(4\,\text{kg}\). Determine every whole-number mass that can be measured using these weights.

Hints

- Add weights that are placed on the same pan opposite the object. - Subtract weights placed beside the object from weights placed on the opposite pan. - Organize the cases by using one weight, two weights, and all three weights. - Remove repeated results from your final list.

Solution

1. Using one weight measures \(1\,\text{kg}\), \(2\,\text{kg}\), or \(5\,\text{kg}\). 2. Placing two weights opposite the object gives sums \(1+2=3\), \(1+5=6\), and \(2+5=7\). Placing one weight beside the object gives differences \(2-1=1\), \(5-1=4\), and \(5-2=3\). 3. Using all three weights gives \(1+2+5=8\) when they are together. With weights on both pans, the positive differences are \(5+2-1=6\), \(5+1-2=4\), and \(5-2-1=2\). 4. Combining the distinct results gives every whole-number mass from \(1\,\text{kg}\) through \(8\,\text{kg}\).

Answer

\(1\,\text{kg}\), \(2\,\text{kg}\), \(3\,\text{kg}\), \(4\,\text{kg}\), \(5\,\text{kg}\), \(6\,\text{kg}\), \(7\,\text{kg}\), and \(8\,\text{kg}\)

All problems may be used, copied and printed free of charge for school and tutoring, including paid tutoring. Commercial adaptations as well as publication or redistribution on the internet are not permitted.