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

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 honeycomb cell has six equal sides, each measuring 8mm. What is its perimeter?

Correct answer: C

Rationale: To find the perimeter of a shape with equal sides, you multiply the length of one side by the number of sides. In this case, the honeycomb cell has 6 sides, each measuring 8mm. Therefore, the perimeter is calculated as perimeter = number of sides * side length = 6 * 8mm = 48mm. Choices A, B, and D are incorrect because they do not correctly calculate the total length around the honeycomb cell with six sides.

3. Express the ratio of 25:80 as a percentage.

Correct answer: A

Rationale: To express the ratio 25:80 as a percentage, follow these steps: First, divide 25 by 80: 25/80 = 0.3125. Then, multiply by 100 to convert to a percentage: 0.3125 × 100 = 31.25%. Therefore, the ratio 25:80 is equivalent to 31.25%. Choice A is correct. Choice B (34%) is incorrect because it does not accurately represent the ratio 25:80. Choice C (41.25%) and Choice D (43.75%) are also incorrect as they do not match the calculated percentage for the given ratio.

4. What is the probability of rolling an even number on a six-sided die?

Correct answer: A

Rationale: The correct answer is A, 50%. A standard six-sided die has three even numbers (2, 4, 6) out of six possible outcomes. The probability of rolling an even number is therefore 3 out of 6, which simplifies to 50%. Choices B, C, and D are incorrect because they do not accurately reflect the probability of rolling an even number on a six-sided die.

5. A lab test result shows a blood glucose level of 5.5 millimoles per liter (mmol/L). What is the equivalent level in milligrams per deciliter (mg/dL)?

Correct answer: A

Rationale: To convert the blood glucose level from millimoles per liter (mmol/L) to milligrams per deciliter (mg/dL), we need to perform a double conversion. 1 millimole is equivalent to 180.15 milligrams, and 1 liter is equal to 10 deciliters. First, multiply the glucose level (5.5 mmol/L) by the conversion factor for millimoles to milligrams (180.15 mg/mmol), then divide by the conversion factor for liters to deciliters (10 dL/L): 5.5 mmol/L * 180.15 mg/mmol / 10 dL/L ≈ 55 mg/dL. Therefore, the equivalent blood glucose level in mg/dL is 55. Choice A is correct. Choice B is incorrect as it does not account for the conversion factors properly. Choices C and D are significantly off as they do not follow the correct conversion calculations.

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