Students of a class are made to stand in rows. If one student is extra in a row, there would be 2 rows
let the number of rows be x and number of students in one row be y.
therefore total number of students = xy.
if one student is extra in a row , there will be 2 rows less.
the number of students in 1 row = y+1. and the number of rows = x-2.
therefore the number of students =
if 1 student is less in a row there would be 3 rows more.
adding eq(1) and eq(2):
thus the number of students in the class = xy = 12*5 = 60
hope this helps you.