Step-by-step explanation:
Let the sum of rupee be x
no of boys be y
then each boy get x/y
now if the no of boys increased by 10 each boy get x/(y+10) = (x/y)-1 => x/(y+10) = (x-y)/y .........(1)
now case 2nd if no of boys decrease by 15 each boy get x/(y-15)= (x/y) +3 => x/(y-15) = (x+3y)/y ...........(2)
