Let x be the original no. of rows & y be the original no. of student s in each row.
Total no. of students = xy.
Acc. to problem
(y + 1) (x - 2) = x y ....(i)
and (y - 1) (x + 3) = xy ....(ii) Solving (i) & (ii) to get
x = 12 & y = 5
Total no. of students = 60