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. How many kilograms are equivalent to 20 pounds?

Correct answer: A

Rationale: To convert pounds to kilograms, you need to multiply the number of pounds by 0.4536. Therefore, to find out how many kilograms are in 20 pounds, you would calculate 20 x 0.4536 = 9.072 kilograms, which is approximately 9 kilograms. Choice A is correct. Choice B (16 kilograms), Choice C (44 kilograms), and Choice D (3 kilograms) are all incorrect conversions of pounds to kilograms.

3. What is the result of subtracting 8.4 from 3.7?

Correct answer: D

Rationale: To find the result of subtracting 8.4 from 3.7, you need to subtract 3.7 from 8.4. Performing this subtraction, 8.4 - 3.7 equals 4.7. Therefore, the correct answer is 4.7. Choice A, 4.5, is incorrect as it is not the result of subtracting 8.4 from 3.7. Choices B and C, 4.8 and 4.6 respectively, are also incorrect as they do not match the correct subtraction result of 4.7.

4. A teacher's aide is preparing a snack for the class. In order to prepare the powdered drink, the aide must convert the directions to metric. The directions say, 'Dilute contents of package in 3 quarts of water.' The aide has a measuring device marked in liters. How many liters of water should be used?

Correct answer: B

Rationale: 3 quarts is approximately 2.8 liters. To convert quarts to liters, multiply the number of quarts by 0.946353. Therefore, the correct answer is 2.8 liters. Choice A (3.0 liters) is incorrect as it does not accurately convert 3 quarts to liters. Choice C (2.5 liters) is incorrect as it is less than the correct conversion. Choice D (3.5 liters) is incorrect as it is more than the correct conversion.

5. Simplify the expression: -5 + (-8)

Correct answer: A

Rationale: When adding two negative numbers, you add their absolute values and keep the negative sign. In this case, -5 + (-8) is equal to -13 because the absolute values of 5 and 8 add up to 13, and the negative sign is retained. Choice B (8) is incorrect because adding two negative numbers results in a negative sum. Choice C (13) is incorrect as it doesn't consider the negative signs of the numbers being added. Choice D (-5) is incorrect because it does not account for the addition of the two negative numbers.

Similar Questions

How many milliliters are in 1 liter?
What is 75% of 80?
Convert the percentage to a decimal: 38% =
Convert to metric: 7 grams = x milligrams
Subtract 12 1/8 - 9 1/2.

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