Correct Answer: A

Rationale: 1/2 oz of perfume is equal to approximately 15 mL. To convert ounces to milliliters, we need to know that 1 oz is approximately 30 mL. Therefore, half an ounce, which is 1/2 oz, would be half of 30 mL, which equals 15 mL. Choice B, 20 mL, is incorrect as it does not correspond to the conversion factor of 1 oz to 30 mL. Choice C, 10 mL, is incorrect as it is half of the actual value. Choice D, 50 mL, is incorrect as it is the value of 1 oz rather than half an ounce.

Correct Answer: A

Rationale: To find the total weight of the delivery, you need to multiply the number of boxes (36) by the weight of each box (2.5 pounds). This gives you 36 boxes * 2.5 pounds = 90 pounds, which is the correct answer. Choice B (75 pounds), C (120 pounds), and D (100 pounds) are incorrect because they do not correctly calculate the total weight based on the given information.

Correct Answer: A

Rationale: To subtract 7 7/10 from 3 4/5, first convert 3 4/5 to have the same denominator as 7 7/10. Converting 4/5 to 8/10, the subtraction becomes 7 7/10 - 3 8/10. Subtracting, 7 - 3 = 4 and 7/10 - 8/10 = -1/10. Therefore, the result is 3 4/5 - 7 7/10 = 3 9/10. Choices B, C, and D are incorrect because they do not reflect the correct subtraction of fractions and whole numbers in this scenario.

Correct Answer: B

Rationale: To divide 40.3 by 4.8, you perform the calculation: 40.3 · 4.8 ≈ 8.4. Therefore, the correct answer is 8.4. Choice A (7.5) is incorrect as it is the result of dividing 40.3 by 5.4. Choice C (6.2) is incorrect as it is the result of dividing 40.3 by 6.5. Choice D (9.1) is incorrect as it is the result of dividing 40.3 by 4.4.

Correct Answer: B

Rationale: To find the total time, add the times for each set of 6 miles: 1 + 1.2 + 1.5 + 1.6 = 5.3 hours. Therefore, it took her 5.3 hours to complete the 24-mile course. Choice A, 5 hours, is incorrect because the total time is slightly more than that. Choice C, 4 hours, is incorrect as it doesn't account for the total time taken. Choice D, 6 hours, is incorrect as it's an overestimation of the actual time taken.