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 ounces are in 4.5 quarts?

A. 120 ounces
B. 120 ounces
C. 144 ounces
D. 128 ounces

Correct answer: C

Rationale: There are 32 ounces in a quart, so to find out how many ounces are in 4.5 quarts, you need to multiply 4.5 by 32. 4.5 quarts * 32 ounces/quart = 144 ounces. Therefore, the correct answer is 144 ounces. Choices A, B, and D are incorrect because they do not correctly calculate the conversion from quarts to ounces.

3. What is the result of multiplying 10 by 5?

A. 65
B. 50
C. 45
D. 55

Correct answer: B

Rationale: The correct answer is B. To find the result of multiplying 10 by 5, you perform the calculation: 10 × 5 = 50. Choices A, C, and D are incorrect because they do not represent the accurate product of 10 multiplied by 5.

4. What factor is used to convert pounds to kilograms?

A. 1.8
B. 2.2
C. 2.5
D. 2

Correct answer: B

Rationale: The correct factor to convert pounds to kilograms is 2.2. To perform the conversion, you need to divide the number of pounds by 2.2. Choice A (1.8) is incorrect as it's not the standard conversion factor. Choice C (2.5) and Choice D (2) are also incorrect factors for converting pounds to kilograms.

5. Your supervisor instructs you to purchase 240 pens and 6 staplers for the nurse's station. Pens are purchased in sets of 6 for $2.35 per pack. Staplers are sold in sets of 2 for $12.95 each. How much will purchasing these products cost?

A. $162.00
B. $132.00
C. $225.00
D. $145.00

Correct answer: B

Rationale: To find the total cost, first calculate the cost of pens and staplers separately. 240 pens require 40 packs (240 pens ÷ 6 pens per pack = 40 packs). Each pack of pens costs $2.35, so 40 packs cost $94 (40 packs × $2.35 per pack = $94). For the staplers, 6 staplers require 3 packs (6 staplers ÷ 2 staplers per pack = 3 packs). Each pack of staplers costs $12.95, so 3 packs cost $38.85 (3 packs × $12.95 per pack = $38.85). Adding the cost of pens and staplers together gives a total of $132.85, which rounds to $132.00. Therefore, the correct answer is $132.00. Choice A is incorrect as it does not consider the individual prices of pens and staplers. Choice C is incorrect as it overestimates the total cost by combining the costs incorrectly. Choice D is incorrect as it underestimates the total cost by not considering both pens and staplers.