Question

A number is increased by 20% and then again by 20%. By what per cent should the increased number be reduced so as to get back the original number ?

• A. $30\frac{5}{9}\%$
• B. $40\frac{5}{9}\%$
• C. $40$
• D. $30$

Answer 1

The correct option is A $30\frac{5}{9}\%$

Let the original number be 100.

An increase of 20% followed by another increase of 20%

$=\frac{120}{100}\times \frac{120}{100}\times 100=144$
$\therefore$ Required decrease = 44 Required % decrease = $\frac{44}{144}\times 100\%$

$=\frac{275}{9}\%=30\frac{5}{9}\%$