Class 2P and Class 2Q have a total of 24 students. ¹₃ of the students in Class 2P and ³₅ of the students in Class 2Q are girls. The number of boys in Class 2P is equal to the number of boys in Class 2Q. Find the total number of boys in the 2 classes.
Fraction of Class 2P that are boys
= 1 - ¹₃ 
= ²₃

Fraction of Class 2Q that are boys
= 1 - ³₅ 
= ²₅ 
 
The number of boys in Class 2P is equal to the number of boys in Class 2Q.

The numerators are the same.  

²₃ Class 2P = ²₅ Class 2Q 

Number of students in Class 2P = 3 u
Number of students in Class 2Q = 5 u

Total number of students 
= 3 u + 5 u
= 8 u

8 u = 24

1 u = 24 ÷ 8 = 3

Number of boys in Class 2P =2 u
Number of boys in Class 2Q =2 u

Total number of boys
= 2 u + 2 u
= 4 u
= 4 x 3
= 12

Answer(s): 12