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. A teacher's aide must convert the directions from quarts to liters. The directions say to dilute the contents of a package in 3 quarts of water. How many liters should be used?

A. 2.8 liters
B. 3.5 liters
C. 2.5 liters
D. 4.0 liters

Correct answer: A

Rationale: To convert quarts to liters, you can multiply the number of quarts by 0.946353. In this case, 3 quarts is approximately 2.8 liters. Therefore, the correct answer is 2.8 liters. Choices B, C, and D are incorrect as they do not reflect the accurate conversion from quarts to liters.

3. What is the probability of rolling a 4 on a six-sided die?

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

Correct answer: B

Rationale: The correct answer is B: 1/6. When rolling a six-sided die, there is only one outcome that results in a '4' out of a total of six possible outcomes (1, 2, 3, 4, 5, 6). Therefore, the probability of rolling a 4 is 1/6. Choice A (1/2) is incorrect as it represents the probability of rolling an even number on a six-sided die, not specifically a '4.' Choice C (1/3) and Choice D (1/2) do not accurately reflect the probability of rolling a '4' on a six-sided die.

4. What is 40% of 150?

A. 60
B. 65
C. 70
D. 85

Correct answer: A

Rationale: To find 40% of 150, you multiply 150 by 0.40 (which represents 40% in decimal form). This calculation results in 60. Therefore, choice A, 60, is the correct answer. Choice B (65), choice C (70), and choice D (85) are incorrect as they do not reflect the accurate calculation for finding 40% of 150.

5. How many millimeters are in 4 meters?

A. 400 mm
B. 4000 mm
C. 40 mm
D. 100 mm

Correct answer: B

Rationale: To convert meters to millimeters, you need to know that there are 1000 millimeters in 1 meter. Therefore, to find out how many millimeters are in 4 meters, you multiply 4 (meters) by 1000 (millimeters per meter), which equals 4000 millimeters. Choice A, 400 mm, is incorrect because it represents 4 decimeters, not 4 meters. Choice C, 40 mm, is incorrect because it represents 4 centimeters, not 4 meters. Choice D, 100 mm, is incorrect because it represents 1 meter, not 4 meters.