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A triangle has dimensions of 9 cm, 4 cm, and 7 cm. The triangle is reduced by a scale factor of x. Which of the following represents the dimensions of the dilated triangle?
- A. 8.25 cm, 3.25 cm, 6.25 cm
- B. 4.5 cm, 2 cm, 3.5 cm
- C. 6.75 cm, 3 cm, 5.25 cm
- D. 4.95 cm, 2.2 cm, 3.85 cm
Correct Answer: C
Rationale: When reducing a figure by a scale factor, each dimension is multiplied by the same scale factor. In this case, the scale factor is not provided in the question. To find the scale factor, you would divide the new lengths of the sides by the original lengths. The scaled-down triangle's dimensions are the original dimensions multiplied by the scale factor. By performing the calculations, the dimensions of the dilated triangle are 6.75 cm, 3 cm, and 5.25 cm, which matches choice C. Choices A, B, and D have incorrect dimensions as they do not result from the correct application of the scale factor to the original triangle's dimensions.
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Sally wants to buy a used truck for her delivery business. Truck A is priced at $450 and gets 25 miles per gallon. Truck B costs $650 and gets 35 miles per gallon. If gasoline costs $4 per gallon, how many miles must Sally drive to make truck B the better buy?
- A. 500
- B. 7500
- C. 1750
- D. 4375
Correct Answer: D
Rationale: To determine the breakeven point where Truck B becomes the better buy, we need to compare the total costs for both trucks. For Truck A: Total cost = $450 + (miles / 25) * $4. For Truck B: Total cost = $650 + (miles / 35) * $4. To find the point where Truck B is the better buy, set the two total cost equations equal to each other and solve for miles. By solving this equation, we find that Sally must drive 4375 miles for Truck B to be the better buy. Choice A (500) is too low, Choice B (7500) is too high, and Choice C (1750) does not represent the breakeven point where Truck B becomes more cost-effective.
Order the groups from largest to smallest, according to the number of doctors in each group.
- A. Group X, Group Y, Group Z
- B. Group Z, Group Y, Group X
- C. Group Z, Group X, Group Y
- D. Group Y, Group X, Group Z
Correct Answer: B
Rationale: The correct order from largest to smallest number of doctors in each group is Group Z (20 doctors), Group Y (15 doctors), and Group X (10 doctors). Therefore, the correct order is Group Z, Group Y, and Group X, which matches option B. Option B is correct because it correctly reflects the descending order of the number of doctors in each group. Options A, C, and D are incorrect as they do not follow the correct order of the number of doctors in each group.
Adrian measures the circumference of a circular picture frame with a radius of 3 inches. Which of the following is the best estimate for the circumference of the frame?
- A. 12 inches
- B. 16 inches
- C. 18 inches
- D. 24 inches
Correct Answer: C
Rationale: The circumference of a circle is given by the formula Circumference = 2 x π x radius. Given that the radius of the picture frame is 3 inches, the estimated circumference can be calculated as 2 x π x 3 = 18.84 inches, which is closest to 18 inches among the given options. Choice A (12 inches) is too small, choice B (16 inches) is also underestimated, and choice D (24 inches) is too large based on the calculated value using the formula.
What is the volume of a ball with a diameter of 7 inches?
- A. 165.7 in³
- B. 179.6 in³
- C. 184.5 in³
- D. 192.3 in³
Correct Answer: A
Rationale: To find the volume of a sphere, the formula V = (4/3)πr³ is used, where r is the radius of the sphere. Given that the diameter of the ball is 7 inches, the radius (r) would be half of the diameter, which is 3.5 inches. Plugging this value into the formula: V = (4/3)π(3.5)³ = (4/3)π(42.875) ≈ 165.7 in³. Therefore, the correct answer is A. Choice B, C, and D are incorrect as they do not accurately represent the volume of the ball with a diameter of 7 inches.
A commuter survey counts the people riding in cars on a highway in the morning. Each car contains only one man, only one woman, or both one man and one woman. Out of 25 cars, 13 contain a woman and 20 contain a man. How many contain both a man and a woman?
- A. 4
- B. 7
- C. 8
- D. 13
Correct Answer: C
Rationale: Let's denote the number of cars containing only a man as M, only a woman as W, and both a man and a woman as B. Given that there are 25 cars in total, we have:
M + W + B = 25
From the information provided, we know that 13 cars contain a woman (W) and 20 cars contain a man (M). Since each car contains either one man, one woman, or both, the cars that contain both a man and a woman (B) are counted once in each of the M and W categories. Therefore, to find out how many cars contain both a man and a woman, we need to subtract the number of cars that contain only a man and only a woman from the total cars.
M + B = 20 (as 20 cars contain a man)
W + B = 13 (as 13 cars contain a woman)
Solving the above two equations simultaneously, we get:
M = 12, W = 5, B = 8
Therefore, 8 cars contain both a man and a woman. Hence, the correct answer is 8. Choice A, B, and D are incorrect as they do not reflect the correct calculation based on the information provided.