Correct Answer: B

Rationale: Rationale: 1. Let x be the volume of the 10% solution needed and y be the volume of water needed. 2. The total volume of the final solution is 200ml, so x + y = 200. 3. The concentration of the final solution is 5%, so the amount of salt in the final solution is 0.05 * 200 = 10g. 4. The amount of salt in the 10% solution is 0.1x, and the amount of salt in the water is 0, so the total amount of salt in the final solution is 0.1x. 5. Since the total amount of salt in the final solution is 10g, we have 0.1x = 10. 6. Solving for x, we get x = 100ml. 7. Substituting x =

Correct Answer: D

Rationale: To calculate how many miles Stanton runs in a year, we first find out how many miles he runs in a week. Running 2 miles twice a week is 2 x 2 = 4 miles, and running 3 miles once a week is an additional 3 miles. Therefore, in a week, Stanton runs a total of 4 + 3 = 7 miles. To find out how many miles he runs in a year, we multiply the weekly total by the number of weeks in a year (52): 7 miles/week x 52 weeks = 364 miles. Therefore, Stanton runs 364 miles in a year. Choice A (185) is incorrect as it does not account for the total weekly distance correctly. Choice B (260) is incorrect as it miscalculates the total miles run in a year. Choice C (330) is incorrect as it does not calculate the correct total distance covered by Stanton in a year.

Correct Answer: A

Rationale: The correct answer is A: 0.5 liters. To convert milliliters to liters, you need to divide by 1000 since there are 1000 milliliters in 1 liter. Therefore, 500 milliliters is equal to 0.5 liters. Choice B, 5 liters, is incorrect because it would be the equivalent of 5000 milliliters. Choice C, 50 liters, is incorrect as it is ten times the converted value. Choice D, 500,000 liters, is way off as it is a thousand times more than the correct conversion.

Correct Answer: C

Rationale: To convert miles to kilometers, you can use the conversion factor of 1 mile is equal to 1.609 kilometers. Therefore, to find the number of kilometers in 12 miles, you can multiply 12 miles by 1.609 to get 19.2 kilometers. The correct answer is 19.2 kilometers, making choice C the correct option. Choice A (7.5 kilometers) is incorrect because it represents half the correct conversion. Choice B (13.2 kilometers) is incorrect as it does not apply the correct conversion factor. Choice D (22 kilometers) is incorrect and represents an incorrect conversion calculation.

Correct Answer: C

Rationale: To divide 152 by 2, you perform the division operation, which is 152 · 2 = 76. The correct answer is 76. Choices A, B, and D are incorrect. Choice A, 0.0116, is the result of dividing 1 by 152 instead of 152 by 2. Choice B, 0.116, is the result of dividing 1.52 by 2. Choice D, 11.6, is the result of multiplying 152 by 2.