Question

If the length and breadth of a rectangle are increased by 8% and 12% respectively, then by what percent does the area of that rectangle increase?

• A. 22%
• B. 24%
• C. 20%
• D. 20.96%

Answer 1

Answer:

D. 20.96%

Let the initial length and breadth of rectangle be l and b respectively

⇒ New length = l + 8% of l = 1.08l

⇒ New breadth = b + 12% of b = 1.12b

⇒ New area$= 1.08I\times{1.12b} = 1.2096lb$

⇒ Percentage increase$=\frac {(1.2096lb)-(lb)}{lb}\times{100}$

= 20.96%