There were an equal number of boys in Class D and Class E. ³₄ of the students in Class D and ¹₆ of the students in Class E are girls. If there are 98 more girls in Class D than in Class E, what is the total number of students in Class D and Class E?
Fraction of the students in Class D that are boys
= 1 - ³₄
=  ¹₄

Fraction of the students in Class E that are boys
= 1 - ¹₆
= ⁵₆ 

The number of boys in Class D is equal to the number of boys in Class E. LCM of 1 and 5 is 5. Make the numerators the same. 

 1x54x5 Class D = 56 Class E 
 520 Class D = 56 Class E

Number of boys in each class = 5 u

Total number of students in Class D = 20 u
Total number of students in Class E = 6 u

Number of girls in Class D
= 20 u - 5 u
= 15 u

Number of girls in Class E
= 6 u - 5 u
= 1 u

Number of more girls in Class D than Class E
= 15 u - 1 u
= 14 u

14 u = 98

1 u = 98 ÷ 14 = 7

Total number of students
= 20 u + 6 u
= 26 u
= 26 x 7
= 182

Answer(s): 182