Question

The percentage increase in the area of a rectangle, if each of its side is increased by 20% is

• A. 40%
• B. 44%
• C. 42%
• D. 46%

Answer 1

The correct option is B

44%

Let original length = x meters and original breadth = y meters
Original area = (x y) $m^2$
New length $=\left[\frac{120x}{100}\right]m=\left[\frac{6x}{5}\right]m$
New Breadth $=\left[\frac{120y}{100}\right]m=\left[\frac{6x}{5}\right]m$
New Area $=[\frac{6x}{5}\times \frac{6y}{5}]m^2$ $=\left[\frac{36}{25}xy\right]m^2$
The difference between the original area = x y and new - area $\frac{36}{25}$ x y is
$=\frac{36}{25}xy-xy=\frac{11}{25}xy$