Question

The breadth of a rectangle is 4 cm less than its length. If the length is increased by 4 cm and the
breadth is decreased by 1 cm, the area of the rectangle is increased by 40 cm. Find the length and
breadth of the rectangle.​

Answer 1

let the length of the rectangle be x cm

then breath = (x-4)cm

area of the rectangle = x(x-4)

=(x²-4x)

as per the question:

(x+4)(x+4-1) = (x²-4x)+40cm²

(x+4)(x-5) = x²-4x+40

x²-x-20 = x²-4x+40

x²-x = x²-4x+20+60

-x+4x = 60

3x = 60

x = 20

length=20

breadth= x-4 = 20-4 = 16