HESI A2 Math Portion

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: 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: B

Rationale: 1 liter is equal to 1,000 cubic centimeters. Therefore, when the oxygen flow rate is 4 liters per minute, the calculation is 4 x 1,000 = 4,000 cubic centimeters. Hence, at a flow rate of 4 liters per minute, 4,000 cubic centimeters of oxygen are delivered per minute. Choice A, 400 cubic centimeters, is incorrect because it miscalculates the conversion from liters to cubic centimeters. Choices C and D, 40,000 cubic centimeters and 400,000 cubic centimeters, respectively, are significantly higher than the correct answer due to incorrect conversions or additional errors in calculation.

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: D

Rationale: The surface area of a cube is calculated using the formula: 6 * (side length)^2. Substituting the side length of 5cm into the formula, we get: 6 * (5cm)^2 = 6 * 25cm^2 = 150 sq cm. Therefore, the total surface area of the toy block is 150 sq cm. Choices A (25 sq cm), B (50 sq cm), and C (125 sq cm) are incorrect as they do not correctly calculate the total surface area of the cube.