Question

A number is increased by $20\%$. By what percent the new number is decreased so hat the number restores the original value?

• A. $15.34\%$
• B. $16.03\%$
• C. $16.67\%$
• D. $17.23\%$

Answer 1

Answer: (C)

$16.67\%$

Let the number be x

$20\%$ of $x=\frac{20}{100}\times x=\frac{x}{5}$

The increased number is $=x+\frac{x}{5}=\frac{6x}{5}$

Let the percentage decrease be 100-y

$\frac{y}{100}\times \frac{6x}{5}=x$

$y=\frac{500}{6}=83.33\%$

So $100-y=100-83.33=16.67$

Percentage decrease should be $16.67\%$