Question

The percentage increase in the perimeter of a rectangle, if each of its sides is increased by $20\%$.

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

Let the original length = 100 m and y = 50 m

So, it perimeter = 2(100 + 50) = 300 m

Now, increased length = 100 + 100 $\times$ $\left(\frac{20}{100}\right)$ = 120 m

Increased breadth = 50 + 50 $\times$ $\left(\frac{20}{100}\right)$ = 60 m

Therefore, perimeter = 2 (120 + 60) = 360 m

Difference in perimeter = (360 - 300) m = 60 m

$\%$ increased = $\left(\frac{60}{300}\right)$ $\times$ $100\%$ = $20\%$