Pets and Players

 

Jonathan's class of 36 has taken a survey of students. Among other survey results were the following:

 

The ratio of those who play sports to the total surveyed is 7 : 12. Among the sports players, the ratio of sports players who are pet owners to the total number of sports players is 3 : 7.

 

How many of the sports players are not pet owners?

 

Hint: Make use of equivalent fractions.