Question

can any one please tell the solution for question # 14

Answer 1

Ans is c) 120

Let the no. of boys be x and no. of girls be y 
then, according to first situation, 
x=y 
⇒x-y = 0 ...(1)

and when 20 girls are added then, 
x/y+20 = 3/4
⇒4x-3y = 60 ...(2)

multiplying equation (1) by 4 we get
4x-4y =0...(3)

Subtracting (3) from (1) we get 

y = 60

since no. of students is x + y and originally x=y
Therefore no. of students = 60+60 = 120