## SAT SUBJECT TEST MATH LEVEL 1

## ALGEBRA

## CHAPTER 7

Word Problems

### PERCENT PROBLEMS

If you have any difficulty with problems involving percents, including percent increase and percent decrease, review the material on percents in Chapter 3.

**EXAMPLE 4:** There are twice as many girls as boys in a biology class. If 30% of the girls and 45% of the boys have completed a lab, what percent of the students in the class have not yet completed the lab?

If *x* represents the number of boys in the class, then 2*x* represents the number of girls in the class. Then of the 3*x* students in the class, the number of students who have completed the lab is

The fraction of students who have completed the lab is

So 65% of the students have not yet completed the lab.