Question

if the length of a rectangle is increased by 8m its area increase by 72 sq.m. the breadth of the rectangle is ?

Answer 1

Define x and y:

Let the breadth be x and the length be y

The length is increased by 8

⇒ Length = y + 8

The area is increased by 72

⇒ Area = xy + 72

Solve x:

Area = Length x Breadth

x(y + 8) = xy + 72

xy + 8x = xy + 72

8x = 72

x = 72 ÷ 8

x = 9

Answer: The breadth is 9 cm

Answer 2

Here is the solution for this question: Let the breadth be b and the length be l. Area of rectangle = l ×b, new length = l+8, new area = lb +72sq.m.

So, (l+8) ×b = lb+72 = lb+8b =lb+ 72.

Now cancel lb on both the sides, 8b=72, Now the breadth of the rectangle is 9