Percentage: Formula and Tricks with Problem (Question) and Solutions

The meaning of per cent is “per hundred” or “hundredth value”. Per cent is a fraction where denominator is 100 . Percent is denoted by sign ” % “.

Important points related to percentage are

1. To convert a fraction or decimal fraction into percentage multiply the fraction by 100.

Ex: 0.035%=0.035×100%=3.5%

2. To convert a percentage into a fraction or decimal fraction, remove sign “%” and divide the value by 100.

Important Formulae

Formula 1

Ex: The percentage change in a number when it is first decreased by 10% and then increased by 10%, is

(a) 0.1% increase
(b) 1% decrease
(c) 0.1% decrease
(d) No changes

Formula 2

Ex: The price of an article is first increased by 20% and later on the price was decreased by 25% due to reduction in sales. Find the net percentage change in final price of article.

(a) 10% decrease
(b) 5% increase
(c) 20% increase
(d) 12% decrease

Formula 3

(a) (b) (c) (d)

Formula 4

Formula 5

Ex: Gaurav spends 30% o of his monthly income on food articles, 40% of the remaining on conveyance and Clothes and saves 50% of the remaining. If his monthly salary 18400, how much money does he save every month?

(a) 3624

(b) 3864

(c) 4264

(d) 5888

Formula 6

Ex: The population of a town increases by 5% every year. If the present population is 9261 , the population 3 yr ago was

(a) 8000

(b) 5700

(c) 6000

(d) 7500

Formula 7