Finding a Percent of a Number

 $\frac{part}{total}\ =\ \frac{\%}{100}$  

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 ?

Jerry, an electrician, worked 7 months out of the year. What percent of the year did he work ?

There are 28 students in a class. Sixteen of those students are men. What percent of the class are women ?

A metal bar weighs 8.15 ounces. 7.533 ounces of the bar is silver. What percent of the bar is silver ?

A customer put $580 into their savings account for one year. What is the bank's rate of interest if the customer earned $37.70 for the year ?