Question

If the length and breadth of a room are increased by 1 m the area is increased by 21 sq m

Answer 1

let l is length and b is breadth

area = l*b

also according to ques

area +21 = (l+1)*(b+1)

area +21 = l*b + l +b+1 equation 1

put area = l*b in equation 1

21 = l+b+1

l+b =20

perimeter = 2*(l+b)

perimeter = 40 m