Question

A rectangle has width a and length b. If the width is decreased by 20% and the length is increased by 10%, then what is the area of the new rectangle in percentage compared to `ab'?

• A. 80%
• B. 88%
• C. 110%
• D. 120%
• E. 119%

Answer 1

The correct option is B

88%

New area = $\left(\frac{80}{100}a\times \frac{110}{100}b\right)=\left(\frac{4}{5}\times \frac{11}{10}ab\right)=\left(\frac{22}{25}ab\right)$

Required percentage = $\left(\frac{22}{25}ab\times \frac{1}{ab}\times 100\right)\%=88\%$