The price of a vacuum cleaner is increased by 25%. By what percent should the price of the vacuum cleaner be decreased to bring it back to the original price?
Solution
Let the original price be Rs. 100
$\therefore$ The price after 25% increase
$= (1.25)\times 100 = Rs.125$
The required percentage decrease
$=\dfrac {125-100}{125}\times 100=20\%$