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. What number is 80 125% of?

A. 48
B. 64
C. 68
D. 78

Correct answer: B

Rationale: To find the number that 80 is 125% of, we can set up the equation: x = 80 / 1.25. Solving this equation gives x = 64. Therefore, 80 is 125% of 64. Choice A (48) is incorrect because it is not the correct value that 80 is 125% of. Choice C (68) is incorrect as it is not the value that satisfies the given percentage relationship. Choice D (78) is incorrect as it does not match the calculation result.

3. A family uses 12 gallons of water every day. How many gallons do they use in a non-leap year?

A. 4,120 gallons
B. 4,380 gallons
C. 3,840 gallons
D. 4,350 gallons

Correct answer: B

Rationale: To determine the total gallons the family uses in a non-leap year, you have to multiply the daily consumption by the number of days in a non-leap year. So, 12 gallons/day x 365 days = 4,380 gallons used per year. Therefore, the correct answer is B. Choice A is incorrect as it provides an inaccurate total by not considering the total days in a year. Choice C is incorrect as it offers a lower value due to not multiplying the daily usage by the total days in a year. Choice D is incorrect as it doesn't accurately calculate the total gallons used in a non-leap year.

4. Express the ratio of 13:60 as a percentage.

A. 19.50%
B. 21.67%
C. 25.50%
D. 31%

Correct answer: B

Rationale: To express the ratio 13:60 as a percentage, calculate the decimal form of the ratio by dividing 13 by 60: 13/60 ≈ 0.2167. Next, convert this decimal to a percentage by multiplying by 100: 0.2167 x 100 = 21.67%. Choice A, 19.50%, is incorrect as it does not accurately represent the ratio. Choice C, 25.50%, and Choice D, 31%, are also incorrect calculations of the percentage equivalent of the ratio 13:60.

5. What is the probability of rolling a 3 on a six-sided die?

A. 1/6
B. 1/4
C. 1/3
D. 1/2

Correct answer: A

Rationale: The probability of rolling a specific number on a six-sided die is calculated by dividing the favorable outcomes (rolling a 3) by the total possible outcomes. In this case, there is 1 favorable outcome (rolling a 3) out of 6 total possible outcomes (numbers 1 to 6 on the die). Therefore, the probability of rolling a 3 is 1/6. Choice B (1/4), C (1/3), and D (1/2) are incorrect because they do not represent the correct calculation of the probability for rolling a 3 on a six-sided die.