Percentages Concept
Posted by
Ravi Kumar at Thursday, June 23, 2011
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Percentage means "expressing one quantity as per cent".
1.To convert a common fraction into per cent, we multiply the fraction with 100. And put % symbol to the result.
2.To convert a percent into fraction we must remove % symbol., divide it with 100 and simplify the product.
3.If the population of a town(or the length of a tree) is P and annual increase is r% then:
*population after n years = P[1+(r/100)]^n
*population n years ago = P/(1+r/100)^n
4.If the population of a town(or the length of a tree) is P and annual decrease is r% then:
*population after n years = P[1-(r/100)]^n
*population n years ago = P/(1-r/100)^n
