Question

the enrollment in school this year is 552 this is an increase of 15% over last year's enrollment how many where in Rout last year

Answer 1

15 % of 552 is 83(approx)
then
552-83=469

Answer 2

Let last years enrollment be x.

x+(15/100)x = 552

(100x+15x)/100 = 552

115x = 552*100

x = (552*100)/115

x = 480