a lab needs 200ml of a 5 salt solution they only have a 10 solution how much 10 solution and water should be mixed

HESI A2

HESI A2 Math Portion

1. A lab needs 200ml of a 5% salt solution. They only have a 10% solution. How much 10% solution and water should be mixed?

A. 100ml 10% solution, 100ml water
B. 150ml 10% solution, 50ml water
C. 160ml 10% solution, 40ml water
D. 200ml 10% solution, 0ml water

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 =

2. How many digits are in the Hindu-Arabic numeral system?

A. Two
B. Ten
C. Twelve
D. Twenty

Correct answer: B

Rationale: The Hindu-Arabic numeral system consists of ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. These ten digits are used as the fundamental symbols to represent numbers in this numerical system. Choice A, 'Two,' is incorrect as there are more than two digits in the system. Choice C, 'Twelve,' is incorrect as it exceeds the total number of digits in the system. Choice D, 'Twenty,' is incorrect as it overestimates the number of digits present in the Hindu-Arabic numeral system.

3. How many inches are in 1.5 yards?

A. 54 inches
B. 60 inches
C. 72 inches
D. 84 inches

Correct answer: A

Rationale: To convert yards to inches, multiply the number of yards by 36 (since there are 36 inches in a yard). 1.5 yards × 36 inches/yard = 54 inches. Therefore, the correct answer is 54 inches. Choice B, 60 inches, is incorrect as it incorrectly assumes that there are 40 inches in a yard. Choice C, 72 inches, is incorrect as it multiplies 1.5 by 48, which is not the correct conversion factor. Choice D, 84 inches, is incorrect as it multiplies 1.5 by 56, which is not the correct conversion factor.

4. If x = -2 and m = -3, evaluate: xm - 2m

A. 12
B. 6
C. 8
D. 10

Correct answer: A

Rationale: Substitute x = -2 and m = -3 into the expression: (-2) * (-3) - 2 * (-3) = 6 + 6 = 12. Therefore, the correct answer is 12. The mistake in the other choices lies in the calculation. Choice B, 6, is the result of adding the two terms instead of subtracting the second term from the first. Choice C, 8, and Choice D, 10, are also incorrect as they do not follow the correct calculation process.

5. Jan canned 5 gallons of homemade tomatoes. She needs to purchase quart jars to finish the process. How many quart jars will she need to buy for her tomatoes?

A. 10
B. 15
C. 20
D. 25

Correct answer: C

Rationale: To determine the number of quart jars needed, we first need to convert the gallons to quarts. Since 1 gallon equals 4 quarts, 5 gallons will be equal to 5 * 4 = 20 quarts. Therefore, Jan will need to buy 20 quart jars to store her canned tomatoes. Choices A, B, and D are incorrect as they do not correctly convert the gallons to quarts, leading to an incorrect quantity of jars required.