Question

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

• A. 40%
• B. 42%
• C. 44%
• D. 46%
• E. None of these

Answer 1

The correct option is C

44%

Let original length = `x' metres and original breadth = `y' metres Original area = (xy) m${}^2$ New length =$\left(\frac{120}{100}x\right)m=\left(\frac{6}{5}x\right)$m; New breadth = $\left(\frac{120}{100}y\right)m=\left(\frac{6}{5}y\right)m$ New Area = $\left(\frac{6}{5}x\times \frac{6}{5}y\right)m^2=\left(\frac{36}{25}xy\right)m^2$ $\therefore$Increase % = $\left(\frac{11}{25}xy\times \frac{1}{xy}\times 100\right)$