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.

Correct Answer: C

Rationale: Out of all the patients who took the antibiotic, 30% developed an infection. Among those with infections, 5% required hospitalization. To find the percentage of all patients hospitalized, we multiply the two percentages: 30% * 5% = 1.5%. Therefore, 1.5% of all patients were hospitalized. Choice A (1.50%) is the calculated percentage of all patients hospitalized, not 1.50%. Choice B (5%) is the percentage of patients who developed an infection and required hospitalization, not all patients. Choice D (30%) represents the initial percentage of patients who developed an infection, not the percentage hospitalized.

Correct Answer: B

Rationale: When the woman stacks the two bookcases together, the total height will be the sum of the heights of the two bookcases. Therefore, 14 inches (larger bookcase) + 8 inches (smaller bookcase) = 22 inches. So, the stacked bookcases will be 22 inches tall. Choice A is incorrect because it does not account for the total height of both bookcases. Choice C and D are incorrect as they are higher than the combined height of the two bookcases.

Correct Answer: A

Rationale: To find the average speed for the round trip, we calculate the total distance and total time traveled. The total distance for the round trip is 45 miles each way, so 45 miles * 2 = 90 miles. The total time taken for the morning trip is 1 hour and 10 minutes (1.17 hours), and for the evening trip is 1.5 hours. Therefore, the total time for the round trip is 1.17 hours + 1.5 hours = 2.67 hours. To find the average speed, we divide the total distance by the total time: 90 miles / 2.67 hours ≈ 33.7 miles per hour. The closest option is A, 30 miles per hour, making it the correct answer. Choice B (45) is the total distance for the round trip, not the average speed. Choices C (36) and D (40) are not derived from the correct calculations and do not represent the average speed for the round trip.

Correct Answer: C

Rationale: To calculate the fare, first, determine the cost for the distance traveled. Joan traveled a total of 14 miles (8 miles to the flower shop + 6 miles to her mother's place). The first mile costs $50, and the remaining 13 miles cost $50 each, totaling $700 for the distance. Additionally, the driver waited for 9 minutes, which incurs an additional cost of $1.80 (9 minutes x $0.20 per minute). Therefore, the total fare is calculated as: Cost for distance + Cost for waiting time = $50 + $650 + $1.80 = $701.80. Choice A, $650, is incorrect as it does not consider the waiting time cost. Choice B, $710, is incorrect as it does not accurately calculate the total fare. Choice D, $650, is incorrect for the same reason as Choice A. The correct total fare is $701.80.