Question

On increasing the length of a rectangle by 20% and decreasing the breadth by 20%, what is the change in area?

Answer 1

Answer:

Let length be x

Let breadth be y

Area of rectangle = L * B = xy

The length of a rectangle is increased by 20 %

New Length = x+ 20/100x = 1.2x

The breadth decrease by 20 percent

New Breadth = y - 20/100y = 0.8y

New Area =  L * B = 1.2x * 0.8y

Difference in original and new area = xy=0.97xy = 0.04 xy

Change in percentage in area = 0.04xy/xy * 100

                                                   4 %

Hence The area of rectangle is decreased by 4%. ANS.

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