Class 4C and Class 4D have a total of 98 students. ¹₆ of the students in Class 4C and ³₈ of the students in Class 4D are boys. The number of girls in Class 4C is equal to the number of girls in Class 4D. Find the total number of girls in the 2 classes.
Fraction of Class 4C that are girls
= 1 - ¹₆ 
= ⁵₆

Fraction of Class 4D that are girls
= 1 - ³₈ 
= ⁵₈ 
 
The number of girls in Class 4C is equal to the number of girls in Class 4D.

The numerators are the same.  

⁵₆ Class 4C = ⁵₈ Class 4D 

Number of students in Class 4C = 6 u
Number of students in Class 4D = 8 u

Total number of students 
= 6 u + 8 u
= 14 u

14 u = 98

1 u = 98 ÷ 14 = 7

Number of girls in Class 4C =5 u
Number of girls in Class 4D =5 u

Total number of girls
= 5 u + 5 u
= 10 u
= 10 x 7
= 70

Answer(s): 70