if larry can wash 50 cars in 20 minutes how many minutes will it take him to wash 80 cars

HESI A2

HESI A2 Math

1. If Larry can wash 50 cars in 20 minutes, how many minutes will it take him to wash 80 cars?

A. 20 minutes
B. 32 minutes
C. 40 minutes
D. 60 minutes

Correct answer: B

Rationale: To determine how many minutes it will take Larry to wash 80 cars, we first calculate his rate of washing cars per minute: 50 cars / 20 minutes = 2.5 cars per minute. To wash 80 cars, we divide the total number of cars by the cars washed per minute: 80 cars / 2.5 cars per minute = 32 minutes. Hence, it will take Larry 32 minutes to wash 80 cars. Choices A, C, and D are incorrect as they do not align with the correct calculation based on Larry's rate of washing cars.

2. A plan for a house is drawn on a 1:40 scale. If the length of the living room on the plan measures 5 inches, what is the actual length of the built living room?

A. 45 feet
B. 25 feet
C. 15 feet
D. 12 feet

Correct answer: C

Rationale: Since the scale of the plan is 1:40, this means that 1 inch on the plan represents 40 inches in reality. Therefore, the actual length of the living room can be calculated as 5 inches on the plan multiplied by the scale factor of 40, which equals 200 inches. Converting 200 inches to feet gives us 15 feet as the actual length of the built living room. Choice A (45 feet) is incorrect because it miscalculates the conversion from inches to feet. Choice B (25 feet) is incorrect as it does not consider the scale factor provided. Choice D (12 feet) is incorrect as it does not apply the correct scale factor to convert the plan's measurements to reality.

3. A physician wants to prescribe 5 mg of a medication to a patient. The medication comes in a 2-mg dose per 1-mL vial. How many milliliters of the medication should the patient receive?

A. 2.5 mL
B. 2 mL
C. 3 mL
D. 1 mL

Correct answer: A

Rationale: To determine the amount of medication the patient should receive, divide the prescribed dose by the dose per mL in the vial. In this case, 5 mg Ã· 2 mg/mL = 2.5 mL. Therefore, the patient should receive 2.5 mL of the medication. Choice B (2 mL) is incorrect because it does not reflect the correct calculation. Choice C (3 mL) is incorrect as it is higher than the actual amount calculated. Choice D (1 mL) is incorrect as it is lower than the actual amount calculated.

4. Subtract 6 1/2 - 2 2/3.

A. 4 1/6
B. 3 1/3
C. 3 5/6
D. 4 1/3

Correct answer: A

Rationale: To subtract mixed numbers, find a common denominator. Converting 6 1/2 to 6 3/6 and 2 2/3 to 2 4/6, the calculation becomes 6 3/6 - 2 4/6 = 4 1/6. Therefore, the correct answer is A. Choice B (3 1/3) is incorrect as the correct result is not an improper fraction. Choice C (3 5/6) is incorrect as it does not represent the result of the subtraction. Choice D (4 1/3) is incorrect as it does not match the correct calculation.

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

A. -13
B. 8
C. 13
D. -5

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.