Correct Answer: C

Rationale: To convert a decimal to a percent, multiply by 100. In this case, 0.64 100 = 64%. Therefore, the correct answer is C. Choice A (0.64%) is incorrect as it represents the original decimal value in percentage form. Choice B (6.4%) is incorrect as it incorrectly multiplies the decimal value by 10 instead of 100. Choice D (0.064%) is incorrect as it represents the decimal value as a fraction of 1000 instead of 100.

Correct Answer: C

Rationale: To calculate the distance Roger can drive on a full tank, multiply the number of gallons in his tank by the average miles per gallon his car gets. 16 gallons x 25 miles per gallon = 400 miles. Therefore, Roger can drive 400 miles on a full tank. Choice A (41 miles) is incorrect as it does not consider the tank's full capacity. Choice B (100 miles) is incorrect as it does not account for the full tank's capacity and the average miles per gallon. Choice D (320 miles) is incorrect as it miscalculates the total distance based on the given information.

Correct Answer: C

Rationale: The metric system is based on powers of 10, making calculations and conversions easier because each unit increases or decreases by a factor of 10.

Correct Answer: D

Rationale: To convert quarts to ounces, you need to multiply by 32 (1 quart = 32 ounces). Therefore, 2 quarts x 32 ounces/quart = 64 ounces. Hence, there are 64 ounces in 2 quarts. Choices A, B, and C are incorrect because they do not reflect the correct conversion factor from quarts to ounces.

Correct Answer: C

Rationale: Rationale: Given formula: HR = (220 - age) * 0.65 Given heart rate: HR = 136.5 Substitute the given heart rate into the formula: 136.5 = (220 - age) * 0.65 Solve for age: 136.5 = 143 - 0.65age 0.65age = 143 - 136.5 0.65age = 6.5 age = 6.5 / 0.65 age = 10 Therefore, the patient's age is 50 (option C).