Correct Answer: A

Rationale: To solve the proportion 120:x::40:0.5, cross-multiply to get 120 * 0.5 = 40 * x. This simplifies to 60 = 40x. Dividing both sides by 40 gives x = 1.5. Therefore, the correct answer is A. Choice B (60) is incorrect because x is not equal to 60. Choice C (0.167) is incorrect as it does not result from solving the proportion. Choice D (16) is also incorrect because x is not equal to 16.

Correct Answer: D

Rationale: To find 80% of $500, you multiply 0.8 by 500. Therefore, 0.8 x 500 = $400. This means that option D, $400, is the correct answer. Option A, $425, is incorrect because it is higher than the calculated value. Option B, $450, is also higher than the correct answer. Option C, $350, is lower than the calculated value. Hence, the correct answer is D, $400.

Correct Answer: A

Rationale: 32 · (8\9) is the same as 32 (9\8) = 36.

Correct Answer: A

Rationale: To determine the largest fraction, it's helpful to convert them to decimals for easier comparison. Converting the fractions to decimals gives: 3/8 = 0.375, 3/9 = 0.333, 3/6 = 0.5, and 3/7 ≈ 0.429. Therefore, 3/7 is the largest fraction among the given options. Choice B, 3/6, is actually equivalent to 3/6 = 0.5 which is greater than 3/7. Choices C and D are smaller fractions compared to 3/7, making them incorrect.

Correct Answer: C

Rationale: To solve for x, cross-multiply: x/250 = 3/500. This simplifies to x = 1.5. Therefore, the correct answer is 1.5. Choice A (150) is incorrect because it does not account for the division by 250. Choice B (25.5) is incorrect as it is not the correct result of the calculation. Choice D (60) is incorrect as it is not the correct result of the calculation either.