Class 1Q and Class 1R have a total of 126 students. ¹₅ of the students in Class 1Q and ⁵₉ of the students in Class 1R are girls. The number of boys in Class 1Q is equal to the number of boys in Class 1R. Find the total number of boys in the 2 classes.
Fraction of Class 1Q that are boys
= 1 - ¹₅ 
= ⁴₅

Fraction of Class 1R that are boys
= 1 - ⁵₉ 
= ⁴₉ 
 
The number of boys in Class 1Q is equal to the number of boys in Class 1R.

The numerators are the same.  

⁴₅ Class 1Q = ⁴₉ Class 1R 

Number of students in Class 1Q = 5 u
Number of students in Class 1R = 9 u

Total number of students 
= 5 u + 9 u
= 14 u

14 u = 126

1 u = 126 ÷ 14 = 9

Number of boys in Class 1Q =4 u
Number of boys in Class 1R =4 u

Total number of boys
= 4 u + 4 u
= 8 u
= 8 x 9
= 72

Answer(s): 72