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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
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