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. Multiply 12 by 15 and express the result as a decimal:

A. 0.0018
B. 0.018
C. 0.18
D. 1.8

Correct answer: D

Rationale: To find the product of 12 and 15, you simply multiply them together. 12 multiplied by 15 equals 180. To express 180 as a decimal, you divide by 100. Therefore, the correct answer is 1.8. Choices A, B, and C are incorrect as they represent values that are not the correct result of multiplying 12 by 15 and converting it to a decimal.

3. Convert 7 grams to milligrams.

A. 700 mg
B. 7,000 mg
C. 70 mg
D. 0.007 mg

Correct answer: B

Rationale: To convert grams to milligrams, you need to multiply by 1,000 since there are 1,000 milligrams in a gram. Therefore, 7 grams x 1,000 = 7,000 mg. Choice A (700 mg) is incorrect as it represents 700 grams, not milligrams. Choice C (70 mg) is incorrect as it implies that 7 grams is equivalent to 70 milligrams, which is inaccurate. Choice D (0.007 mg) is also incorrect since it represents a fraction of a milligram, significantly less than the original 7 grams.

4. Olivia currently earns $51,200 in her job. If her salary increases by 4% this year, what will her new salary be?

A. $52,348
B. $52,736
C. $53,040
D. $53,248

Correct answer: D

Rationale: To find Olivia's new salary after a 4% increase, we calculate 4% of $51,200, which is 0.04 x $51,200 = $2,048. Adding this increase to Olivia's current salary gives us the new salary: $51,200 + $2,048 = $53,248. Therefore, Olivia's salary after the 4% increase will be $53,248. Choices A, B, and C are incorrect as they do not reflect the correct calculation for the new salary after a 4% increase.

5. A researcher is collecting data on patient satisfaction. Out of 150 patients surveyed, 120 reported being satisfied with their care. What percentage of the patients were satisfied?

A. 80%
B. 75%
C. 85%
D. 90%

Correct answer: A

Rationale: To find the percentage of satisfied patients, divide the number of satisfied patients by the total number of patients surveyed and multiply by 100. In this case, 120 (satisfied patients) ÷ 150 (total patients surveyed) x 100 = 80%. Therefore, 80% of the patients were satisfied. Choice B (75%), C (85%), and D (90%) are incorrect percentages as the actual percentage of satisfied patients is 80%.