Correct Answer: A

Rationale: 1 meter is equal to 1000 millimeters. Therefore, to convert 3000 millimeters to meters, we divide by 1000. 3000 millimeters / 1000 = 3 meters. Choice A, '3 meters,' is the correct answer. Choice B, '30 meters,' is incorrect because it represents a miscalculation of multiplying instead of dividing. Choice C, '0.3 meters,' is incorrect as it is the result of a decimal error. Choice D, '300 meters,' is incorrect as it is a result of not converting millimeters to meters correctly.

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: C

Rationale: The correct answer is 7.3. To subtract 13.4 from 20.7, you align the decimal points and subtract each place value: 0.7 - 0.4 = 0.3, and 2 - 1 = 1. Therefore, 20.7 - 13.4 = 7.3. Choices A, B, and D are incorrect because they do not provide the accurate result of this subtraction.

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 because there are 1,000 milligrams in 1 gram. Therefore, to find out how many milligrams are in 3.4 grams, you multiply 3.4 by 1,000 which equals 3,400 mg. Choices A, C, and D are incorrect because they do not correctly convert grams to milligrams.