Class 5L and Class 5M have a total of 136 students. ¹₆ of the students in Class 5L and ⁶₁₁ of the students in Class 5M are girls. The number of boys in Class 5L is equal to the number of boys in Class 5M. Find the total number of boys in the 2 classes.
Fraction of Class 5L that are boys
= 1 - ¹₆ 
= ⁵₆

Fraction of Class 5M that are boys
= 1 - ⁶₁₁ 
= ⁵₁₁ 
 
The number of boys in Class 5L is equal to the number of boys in Class 5M.

The numerators are the same.  

⁵₆ Class 5L = ⁵₁₁ Class 5M 

Number of students in Class 5L = 6 u
Number of students in Class 5M = 11 u

Total number of students 
= 6 u + 11 u
= 17 u

17 u = 136

1 u = 136 ÷ 17 = 8

Number of boys in Class 5L =5 u
Number of boys in Class 5M =5 u

Total number of boys
= 5 u + 5 u
= 10 u
= 10 x 8
= 80

Answer(s): 80