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

Answer

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Let, breadth of rectangle is x, then 5x−4be the length of the rectangle. 

Perimeter of rectangle =2(l+b)

⇒40=2(l+b)

⇒40=2(5x−4+x)

⇒40=12x−8

⇒12x=40+8

⇒12x=48

⇒x=1248

⇒x=4

Breadth =4 meters 

Hence, length =5×4−4=20−4=16m

Therefore, area of rectangle =lb=16×4=64m2 

Answer 2

Let, the breath of the rectangle be x, then 5x-4 is the length of the rectangle.

The perimeter of the rectangle= 2(l+b)= 40= 2(l+b)= 40- 2(5x-4+x)=40=12x-8

                                                     =12x= 40+8= 12x= 48= x= 1248= x= 4

Hence, the lenght = 5*4-4= 20-4= 16m

Therefore, the area of the rectangle=lb=16x= 64m2