evaluate the following expression x y xy if x 4 and y 2

HESI A2

HESI A2 Math Practice Exam

1. Evaluate the following expression: -x + y + xy, when x = 4 and y = 2.

A. 2
B. 6
C. 12
D. 8

Correct answer: B

Rationale: To evaluate the expression, substitute x = 4 and y = 2 into the expression: -4 + 2 + 4*2. Calculate each term: -4 + 2 = -2, then 4*2 = 8. Adding these results gives -2 + 8 = 6. Therefore, the correct answer is 6. Choice A (2) is incorrect as it does not consider all terms in the expression. Choice C (12) is incorrect as it miscalculates the result by failing to account for the negative sign. Choice D (8) is incorrect as it doesn't consider the negative value of the first term in the expression.

2. What is the result of adding 7/21 + 10/21?

A. 17/21
B. 15/21
C. 9/21
D. 10/21

Correct answer: A

Rationale: When adding fractions with the same denominator, you simply add the numerators while keeping the denominator the same. In this case, 7/21 + 10/21 = 17/21. Therefore, the correct answer is A. Choice B (15/21) is incorrect because it adds the numerators incorrectly. Choice C (9/21) is incorrect as it does not reflect the sum of the fractions provided. Choice D (10/21) is also incorrect as it does not represent the correct sum of the two fractions.

3. Convert 3/4 to a decimal.

A. 0.75
B. 0.5
C. 0.65
D. 0.85

Correct answer: A

Rationale: To convert a fraction to a decimal, divide the numerator by the denominator. In this case, 3 divided by 4 is equal to 0.75. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not represent the equivalent decimal value of 3/4. 0.5 is the decimal equivalent of 1/2, 0.65 is the decimal equivalent of 13/20, and 0.85 is the decimal equivalent of 17/20.

4. 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 ÷ 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.

5. A hospital nurse's schedule rotates every 4 days. The nurse works 3 days and has 1 day off. If the nurse's first day off is a Monday, what is the nurse's second day off?

A. Friday
B. Saturday
C. Thursday
D. Wednesday

Correct answer: A

Rationale: The nurse's schedule repeats every 4 days, with 3 days of work and 1 day off. If the first day off is Monday, then after 4 days (Monday + 4 days), the second day off will fall on Friday. Therefore, the correct answer is A. Choice B (Saturday), C (Thursday), and D (Wednesday) are incorrect as they do not align with the 4-day rotation pattern after the first day off on Monday.