Question

the enrolment in a school this year is 552. this is an increase of 15% over last year's enrolment.how many were enrollment last year?

Answer 1

enrolment this year = 552
let the last year's enrolment be x
 so this year's enrolment is 115x/100
 ATQ,
23x/20=552
⇒x=552X20/23=480
so last year's enrolment was 480 students.

Answer 2

This years enrolment = (last year's enrolment + 15/100 of last years' enrolment)
             552   = 115/ 100 * last years' enrolment

last year's enrolment = 55200/115 = 480 students.