Question

Suppose there are 20 questions on a multiple-choice test. If 25% of the answers are choice B, how many of the answers are not choice B?

Answer 1

This is one method: Part=Percent • Whole
Your part is x since you don't know it yet. Your percent is 25%. Your whole is 20. However, you have to turn 25% into a decimal, which would be .25.
Your new equation is now x=.25•20. When you multiply .25 by 20, you should get 5. Therefore, 5 is how many questions ARE B. However, you need to find the questions that aren't B. This is why you would have to subtract 5 from 20, giving you 15 questions that are NOT B. That would be your final answer.

-

An easier way is to divide you whole by 100 and multiply it by the percentage. 20 divided by 100 is .2. Then you multiply it by 25, giving you 5.

Answer 2

`b: (x)/(20) (25)/(100) \\ 100x=500 \\ x=5 \\ others: 20-5=15`