Question

The area of a rectangular playground is 420 sq.m, If the length is increased by 7 and breadth is decreased by 5, the area of the rectangular playground remains the same, find the length and breadth of the rectangular playground.​

Answer 1

Area = 420 sq m

length x breadth = 420

(l + 7)(b -5) = 420

lb = (l+7)(b-5)

lb = lb - 5l + 7b - 35

-5l + 7b - 35 = lb - lb

7b - 5l = 35

7b = 35 + 5l

b = $\frac{35 + 5l}{7}$ = 5 + $\frac{5l}{7}$ m

-5l = 35 - 7b

l =  $\frac{7b-35}{5}$ = $\frac{7b}{5}$ - 7 m