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: 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: B

Rationale: To convert grams to milligrams, you need to multiply by 1,000 since there are 1,000 milligrams in a gram. Therefore, 7 grams x 1,000 = 7,000 mg. Choice A (700 mg) is incorrect as it represents 700 grams, not milligrams. Choice C (70 mg) is incorrect as it implies that 7 grams is equivalent to 70 milligrams, which is inaccurate. Choice D (0.007 mg) is also incorrect since it represents a fraction of a milligram, significantly less than the original 7 grams.

Correct Answer: C

Rationale: There are 32 ounces in a quart, so to find out how many ounces are in 4.5 quarts, you need to multiply 4.5 by 32. 4.5 quarts * 32 ounces/quart = 144 ounces. Therefore, the correct answer is 144 ounces. Choices A, B, and D are incorrect because they do not correctly calculate the conversion from quarts to ounces.

Correct Answer: B

Rationale: There are 1,000 milliliters in a liter. To convert milliliters to liters, you divide by 1,000. Therefore, 8,000 milliliters · 1,000 = 8 liters. This makes option B the correct answer. Option A, 0.8 liters, is incorrect as it is 1/10th of the correct answer. Option C, 0.8 liters (repeated), is also incorrect. Option D, 0.08 liters, is incorrect as it is 1/100th of the correct answer.