convert 78 to a decimal

HESI A2

HESI A2 Math Practice

1. Convert 7/8 to a decimal.

A. 0.8
B. 0.8
C. 0.875
D. 0.9

Correct answer: C

Rationale: To convert the fraction 7/8 to a decimal, you divide the numerator (7) by the denominator (8): 7 ÷ 8 = 0.875. Therefore, the correct decimal representation of the fraction 7/8 is 0.875. Choice A and B, which are both 0.8, are incorrect as they represent 4/5 and not 7/8. Choice D, 0.9, is also incorrect as it represents 9/10 and not 7/8.

2. Sarah had 1 quart of milk. How many ounces of milk is that?

A. 16 ounces
B. 24 ounces
C. 32 ounces
D. 48 ounces

Correct answer: C

Rationale: The correct answer is 32 ounces. One quart is equivalent to 32 ounces. To convert quarts to ounces, you need to know that 1 quart equals 32 ounces. Therefore, 1 quart of milk is equal to 32 ounces. Choices A, B, and D are incorrect as they do not accurately convert 1 quart to ounces.

3. How many milligrams are in 7 grams?

A. 7000 mg
B. 7 mg
C. 700 mg
D. 70 mg

Correct answer: A

Rationale: To convert grams to milligrams, you need to multiply by 1,000 since there are 1,000 milligrams in a gram. So, 1,000 x 7 grams = 7,000 mg. This means that there are 7,000 milligrams in 7 grams. Choices B, C, and D are incorrect because they do not correctly convert grams to milligrams.

4. Convert the percentage to a decimal: 38%

A. 3.8
B. 0.38
C. 0.038
D. 38.0

Correct answer: B

Rationale: To convert a percentage to a decimal, you divide the percentage by 100. Therefore, 38% as a decimal is 0.38 (38 ÷ 100 = 0.38). Choice A, 3.8, is incorrect as it is equivalent to 380%. Choice C, 0.038, is incorrect as it represents 3.8%. Choice D, 38.0, is incorrect as it is still in percentage form.

5. A pressure vessel has a cylindrical body (diameter 10cm, height 20cm) with hemispherical ends (same diameter as the cylinder). What is its total surface area?

A. 785 sq cm
B. 1130 sq cm
C. 1570 sq cm
D. 2055 sq cm

Correct answer: D

Rationale: To find the total surface area, we need to calculate the surface area of the cylindrical body and both hemispherical ends separately. The surface area of the cylinder is the sum of the lateral surface area (2πrh) and the area of the two circular bases (2πr^2). For the hemispheres, the surface area of one hemisphere is (2πr^2), so for two hemispheres, it would be (4πr^2). Given that the diameter of the cylinder and hemispherical ends is 10cm, the radius (r) is 5cm. Calculating the individual surface areas: Cylinder = 2π(5)(20) + 2π(5)^2 = 200π + 50π = 250π. Hemispheres = 4π(5)^2 = 100π. Adding these together gives a total surface area of 250π + 100π = 350π cm^2, which is approximately equal to 2055 sq cm. Therefore, the correct answer is D. Choice A (785 sq cm) is incorrect as it is significantly lower than the correct calculation. Choices B (1130 sq cm) and C (1570 sq cm) are also incorrect as they do not reflect the accurate surface area calculation for the given dimensions.