Class 4M and Class 4N have a total of 28 students. ¹₅ of the students in Class 4M and ⁵₉ of the students in Class 4N are boys. The number of girls in Class 4M is equal to the number of girls in Class 4N. Find the total number of girls in the 2 classes.
Fraction of Class 4M that are girls
= 1 - ¹₅ 
= ⁴₅

Fraction of Class 4N that are girls
= 1 - ⁵₉ 
= ⁴₉ 
 
The number of girls in Class 4M is equal to the number of girls in Class 4N.

The numerators are the same.  

⁴₅ Class 4M = ⁴₉ Class 4N 

Number of students in Class 4M = 5 u
Number of students in Class 4N = 9 u

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

14 u = 28

1 u = 28 ÷ 14 = 2

Number of girls in Class 4M =4 u
Number of girls in Class 4N =4 u

Total number of girls
= 4 u + 4 u
= 8 u
= 8 x 2
= 16

Answer(s): 16