Solve for x: 7:42 :: 4:x

Correct Answer: B

Rationale: To solve this proportion, set up the equation: 7/42 = 4/x. Cross-multiply to get 7x = 168. Solve for x by dividing both sides by 7, yielding x = 24. Therefore, the correct answer is 24. Choice A (16), Choice C (48), and Choice D (12) are incorrect as they do not satisfy the proportion 7:42 :: 4:x.

Correct Answer: B

Rationale: To convert ounces to milliliters, we know that 1 ounce is approximately 30 mL. Therefore, 0.5 ounces would be half of that, which is 15 mL. So, 0.5 oz of perfume is equal to 15 mL. Choice A (10 mL), Choice C (20 mL), and Choice D (25 mL) are incorrect as they do not reflect the accurate conversion from ounces to milliliters.

Correct Answer: B

Rationale: If two-thirds of the students are boys, then one-third of the students must be girls. One-third of 27 is 9, so there are 9 girls in Mr. Garcia's class. Therefore, the correct answer is 9. Choice A is incorrect because it is too low; only one-third of the students are girls. Choices C and D are incorrect as they do not reflect the correct calculation based on the given information in the question.

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).

Correct Answer: A

Rationale: To convert a percentage to a decimal, you divide by 100. In this case, 38% divided by 100 equals 0.38. Moving the decimal point two places to the left converts the percentage to a decimal. Choice B is incorrect because it incorrectly moves the decimal point one place to the left. Choice C is incorrect as it moves the decimal point three places to the left. Choice D is incorrect as it does not convert the percentage to a decimal.

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: 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: To find the product of 99 and 0.56, multiply the two numbers: 99 x 0.56 = 55.44. Therefore, the correct answer is 55.44.

Correct Answer: B

Rationale: The Roman numeral XVII represents the number 17. In Roman numerals, X stands for 10 and V stands for 5. When V (5) is subtracted from X (10), it results in 5 being subtracted from 10, which equals 5. Adding this to V (5) gives the total value of XVII as 17. Choice A is incorrect because it is not the correct numerical value of XVII. Choice C and D are also incorrect as they do not correspond to the Roman numeral XVII.