ASVAB Mathematics Knowledge Practice: Percentages
The Mathematics Knowledge subtest on the ASVAB contains many problems that involve working with percentages. Although calculating percentages is pretty straightforward, you will definitely find a scratch paper and pencil useful, as you’ll see in the following practice questions.
- 250 is 40 percent of what number?
- What is 55 percent of 150?
Answers and explanations
- The correct answer is Choice (B).
To determine a whole number when you know a part and a percent, you can use a proportion; let x equal the whole. The proportion looks like this:
Plug in the numbers you know:
Cancel out the zeros in the fraction to make the problem a bit easier:
(Remember, though, you can’t cancel out zeros on the other side of the equals sign.)
Divide both sides by 4 to isolate x:
You can check your work by putting the variable in the original equation and making sure the fractions are equal:
- The correct answer is Choice (D).
You can convert 55 percent into a decimal (0.55) and multiply it by 150 to arrive at the answer, which is 82.5, or you can use a proportion where x equals the number you need to find:
Divide each side by 100 to isolate x: