15 is 20 of what number

HESI A2

HESI A2 Math 2024

1. What number is 15, if it is 20% of that number?

A. 3
B. 45
C. 75
D. 300

Correct answer: B

Rationale: To find the number that 15 is 20% of, we set up the equation: x * 0.20 = 15. Solving for x, we get x = 15 / 0.20 = 75. Therefore, 15 is 20% of 75. Choice A, 3, is too small to be 20% of 15. Choice C, 75, is the result of the correct calculation. Choice D, 300, is too large to be 20% of 15.

2. Subtract 12 1/8 - 9 1/2.

A. 2 5/8
B. 3 1/8
C. 4 1/2
D. 4 2/3

Correct answer: A

Rationale: To subtract mixed numbers, first subtract the fractions: 1/8 - 1/2 = -3/8. Then, subtract the whole numbers: 12 - 9 = 3. Combine the whole number and fraction: 3 - 3/8 = 2 5/8. Therefore, the correct answer is A. Choice B is incorrect because it does not reflect the correct subtraction of the fractions. Choices C and D are incorrect as they do not result from the correct subtraction process outlined above.

3. Temperature Conversion & Interpretation: A patient's body temperature is 102°F. Convert this to °C and assess if it indicates a fever.

A. 37�C (Normal)
B. 39�C (Low-grade fever)
C. 39�C (Fever)
D. 42�C (Hyperthermia)

Correct answer: C

Rationale: Rationale: 1. To convert Fahrenheit to Celsius, you can use the formula: °C = (°F - 32) x 5/9. 2. Given that the patient's body temperature is 102°F, we can calculate the equivalent temperature in Celsius: °C = (102 - 32) x 5/9 °C = 70 x 5/9 °C = 350/9 °C ≈ 38.9°C, which can be rounded to 39°C. 3. A body temperature of 39°C is considered to indicate a fever. Normal body temperature typically ranges from 36.1°C to 37.2°C, so a temperature of 39°C is higher than the normal range and suggests a fever. 4. Options A and B are incorrect as they do not reflect the conversion of 102°F to °C

4. A birdbath has a hemispherical bowl with a diameter of 30cm. What is its volume?

A. 675 cu cm
B. 1350 cu cm
C. 2700 cu cm
D. 4050 cu cm

Correct answer: C

Rationale: To find the volume of a hemispherical bowl, we use half the formula for a sphere's volume: (2/3) * π * (radius)^3. Given the diameter is 30cm, the radius is half of that, which is 15cm. Substitute the radius into the formula: (2/3) * π * (15cm)^3 ≈ 2700 cu cm. Therefore, the correct volume is approximately 2700 cu cm. Choices A, B, and D are incorrect as they do not correctly calculate the volume of the hemispherical bowl.

5. Round to the nearest whole number: What is 18% of 600?

A. 108
B. 76
C. 254
D. 176

Correct answer: A

Rationale: To find 18% of 600, you multiply 600 by 0.18, which equals 108. Since 108 is already a whole number, when rounding to the nearest whole number, it remains the same. Choices B, C, and D are incorrect as they do not represent the correct calculation for finding 18% of 600.