The change in the value of an item can be expressed as a percentage increase or decrease of the original value.
An increase of 5% in the salary of a ma n who earns Rs.500 per month means there is an increase of Rs.5 for every hundred (100); i.e. after the increase, Rs.100 becomes 105.
New Salary = x Original Salary = x 500 = 525
On the other hand, a decrease of 5% in his salary means that for every Rs.100 in the original salary, there is a decrease of Rs.5; i.e. each Rs.100 becomes Rs.95/
New Salary = x Original Salary = x 500 = 475
If an amount “” is increased by
If an amount “” is decreased by