Question

The perimeter of a rectangle is 40 m. Its length is four metres less than five times its breadth. Find the area of the rectangle.

Answer 1

Let breadth of the rectangle = x 

Then, length of the rectangle = 5x – 4

We know that,

Perimeter of rectangle = 2(l + b)

⇒ 40 = 2(l + b)  ...[∵ Perimeter = 40 m, given]

⇒ 40 = 2(5x – 4 + x)

⇒ 40 = 2(6x – 4)

⇒ 12x – 8 = 40

⇒ 12x = 40 + 8

⇒ 12x = 48

⇒ x = `48/12` = 4

So, breadth = x = 4 m and length = 5x – 4 = 5 × 4 – 4 = 16 m 

∴ Area of rectangle = l × b = 4 × 16 = 64 m²

Hence, the area of rectangle is 64 m².