A survey of students at a community college shows that 2 in every 3 students register for a math class. Of the students who register for a math class, 1 in every 4 takes precalculus.

Question

 Suppose 15,000 students attend a particular community college.  

a. How many students register for a math class?   

b. How many students register for a precalculus class?

Answer 1

You can answer these questions using equivalent ratios.

a. First the ratio of student staking math to the total can be written in fraction form as :

2 math students

3 total students

Then use the total student population of 15000 to find the number who signed up for math

2 math students = x math students

3 total students 15000 total students

2 math students • 5000 = 10000 math students

3 total students • 5000 15000 total students

10000 students signed up for a math class.

b. To determine the number who registered for a precalculus class using 10000 as the total number of students:

1 precalculus student = y precalculus students

4 total math students 10000 total math students

1 precalculus student • 2500 = 2500 precalculus students

4 total math students • 2500 10000 total math students

2500 students registered for a precalculus class.