HESI A2 Math Practice

Correct Answer: B

Rationale: To calculate the volume needed, we divide the desired dose (1 gram) by the concentration (200 mg/ml) to convert grams to milligrams. 1 gram = 1000 mg. So, 1000 mg / 200 mg/ml = 5 ml. Thus, the correct answer is B: 5 milliliters. Choice A is incorrect because it miscalculates the conversion. Choices C and D are also incorrect as they do not accurately reflect the correct calculation.

Correct Answer: B

Rationale: To solve for x in the equation 3x + 9 = 0, first, subtract 9 from both sides to isolate 3x. This gives you 3x = -9. Next, divide both sides by 3 to solve for x, which results in x = -3. Therefore, the correct answer is B. Choice A is incorrect as it does not account for the correct arithmetic operations. Choice C is incorrect because it does not yield a solution that satisfies the equation. Choice D is incorrect as it does not follow the correct steps to solve for x.

Correct Answer: C

Rationale: To find the total surface area, we calculate the area of the rectangular base (20*15=300 sq cm). Then, we find the surface area of the hemispherical top, which is half the surface area of a sphere with radius 10cm (diameter is the same as the base). So, the surface area of the hemispherical top is 2πr^2 = 2*π*(10)^2 = 200π sq cm. Adding the two areas together (300+200π), we get 300+200π ≈ 300+628.32 ≈ 928.32 sq cm. The correct answer is 1325 sq cm (Option C), which is the total surface area of the box excluding the base. Option A, B, and D are incorrect as they do not represent the accurate total surface area of the box.

Correct Answer: C

Rationale: To convert ounces to pounds, we know that 16 ounces equal 1 pound. Therefore, to find how many pounds are in 192 ounces, we divide 192 by 16, which equals 12 pounds (Option C). Option A is incorrect as it incorrectly converts 192 ounces to 16 pounds. Option B is incorrect as it miscalculates the conversion. Option D is incorrect as it duplicates Option A.

Correct Answer: D

Rationale: To subtract 8.4 from 3.7, we perform 3.7 - 8.4. First, subtract the whole numbers: 3 - 8 = -5. Then subtract the decimals: 0.7 - 0.4 = 0.3. Combine the results to get -5.3. Therefore, the correct answer is option D: 4.7. Option A (4.5) is the result of subtracting the whole numbers but not the decimals. Option B (4.8) and Option C (4.6) are incorrect as they do not result from the correct subtraction calculation.