Detailed Rationales (Updated 2026) | Math Skills & Dosage Calculations,
Reading Comprehension & Vocabulary, Grammar & English Language
Usage, Anatomy & Physiology, Biology & Chemistry Basics, Critical
Thinking Strategies, Study Techniques & HESI A2 Nursing School Entrance
Exam Success
Question 1: What is the result of converting the fraction 5/16 to a decimal?
A. 0.215
B. 0.3125
C. 0.425
D. 0.5625
CORRECT ANSWER: B. 0.3125
Rationale: To convert a fraction to a decimal, divide the numerator by the denominator.
5 ÷ 16 = 0.3125. This skill is essential for medication dosage calculations on the HESI A2
mathematics section.
Question 2: A nurse must administer 0.75 grams of a medication. The available
tablets contain 250 mg each. How many tablets should the nurse administer?
A. 2 tablets
B. 3 tablets
C. 4 tablets
D. 5 tablets
CORRECT ANSWER: B. 3 tablets
Rationale: First convert 0.75 grams to milligrams: 0.75 g × 1000 = 750 mg. Then divide
the required dose by the tablet strength: 750 mg ÷ 250 mg/tablet = 3 tablets. Accurate
unit conversion is critical for safe medication administration.
Question 3: Which of the following represents the correct order of operations when
solving the expression: 8 + 2 × (5 - 3)²?
A. Addition, subtraction, multiplication, exponentiation
B. Parentheses, exponentiation, multiplication, addition
C. Multiplication, addition, parentheses, exponentiation
D. Exponentiation, parentheses, addition, multiplication
CORRECT ANSWER: B. Parentheses, exponentiation, multiplication, addition
Rationale: The order of operations follows PEMDAS: Parentheses first (5-3=2), then
Exponents (2²=4), then Multiplication (2×4=8), and finally Addition (8+8=16). Mastery of
this sequence prevents calculation errors in clinical math.
Question 4: If a patient's heart rate is 72 beats per minute, how many beats occur in
15 seconds?
,A. 12 beats
B. 18 beats
C. 24 beats
D. 36 beats
CORRECT ANSWER: B. 18 beats
Rationale: Since 15 seconds is one-fourth of a minute, divide the per-minute rate by 4:
72 ÷ 4 = 18 beats. Proportional reasoning is frequently tested on the HESI A2 and
applied in vital sign assessments.
Question 5: What is the perimeter of a rectangle with a length of 12 cm and a width
of 5 cm?
A. 17 cm
B. 34 cm
C. 60 cm
D. 120 cm
CORRECT ANSWER: B. 34 cm
Rationale: The perimeter of a rectangle is calculated as 2(length + width). Therefore,
2(12 + 5) = 2(17) = 34 cm. Geometric calculations may appear in dosage or equipment
measurement contexts.
Question 6: Solve for x: 3x + 7 = 22
A. x = 3
B. x = 5
C. x = 7
D. x = 9
CORRECT ANSWER: B. x = 5
Rationale: Subtract 7 from both sides: 3x = 15. Then divide by 3: x = 5. Algebraic
problem-solving supports understanding of formulas used in nursing calculations.
Question 7: A solution contains 40 mg of medication in 5 mL. How many milligrams
are in 12 mL of this solution?
A. 84 mg
B. 96 mg
C. 108 mg
D. 120 mg
CORRECT ANSWER: B. 96 mg
Rationale: Set up a proportion: 40 mg/5 mL = x mg/12 mL. Cross-multiply: 5x = 480.
Solve: x = 96 mg. Ratio and proportion questions are common on the HESI A2 math
section.
, Question 8: Which of the following is equivalent to 25%?
A. 1/5
B. 1/4
C. 1/3
D. 1/2
CORRECT ANSWER: B. 1/4
Rationale: Percent means "per hundred," so 25% = 25/100 = 1/4 when simplified.
Converting between fractions, decimals, and percentages is a foundational math skill
for nursing.
Question 9: A patient is to receive 1.5 liters of IV fluid over 12 hours. What is the
infusion rate in milliliters per hour?
A. 100 mL/hr
B. 125 mL/hr
C. 150 mL/hr
D. 175 mL/hr
CORRECT ANSWER: B. 125 mL/hr
Rationale: Convert liters to milliliters: 1.5 L = 1500 mL. Divide total volume by time: 1500
mL ÷ 12 hr = 125 mL/hr. IV flow rate calculations are essential clinical competencies.
Question 10: What is the area of a circle with a radius of 4 cm? (Use π ≈ 3.14)
A. 25.12 cm²
B. 50.24 cm²
C. 100.48 cm²
D. 200.96 cm²
CORRECT ANSWER: B. 50.24 cm²
Rationale: The area of a circle is πr². Therefore, 3.14 × (4)² = 3.14 × 16 = 50.24 cm². While
less common, geometric formulas may appear in contextual math problems.
Question 11: If a medication order is for 0.5 mg and the available concentration is 2
mg/mL, how many milliliters should be administered?
A. 0.125 mL
B. 0.25 mL
C. 0.5 mL
D. 1 mL
CORRECT ANSWER: B. 0.25 mL
Rationale: Use the formula: Desired dose ÷ Available concentration = Volume. 0.5 mg ÷
2 mg/mL = 0.25 mL. Dimensional analysis is a key strategy for dosage calculations.
Question 12: Which of the following numbers is prime?