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BACK

PERCENTAGES


       By a certain percent, we mean that many hundredths. Thus x  
       per cent means x hundredths written as x%.   
                            So x% = x/100.
       

EXAMPLE:

1.20% = 20/100 = 1/5 2.48% = 48/100 = 12/25
To express a/b as a percent ,we have

a/b=(a/b*100)%

Thus 1/4=(1/4*100)%=25% 0.6=6/10=(3/5*100)%=60% If the price of commodity increases by r%,then the reduction in consumption so as not to increase the expenditure is given as follows [r/(100+r)*100]% If the price of commodity decreased by r%,then the increase in consumption so as not to decrease the expenditure is given as follows [r/(100-r)*100]%

RESULT ON POPULATION:

Let the population of a town be P now and suppose it increases at the rate R% per annum then i)Population after n years = P[1+(R/100)]n ii) Population n years ago= P/[1+(R/100)]n

RESULT ON DEPRECIATION:

Let the present value of a machine be P. Suppose it depriciates at the rate of R% per annum, then i)Value of machine after n years = P[1-(R/100)]n ii)Value of machine after n years = P/[1-(R/100)]n

IMPORTANT

i) If A is R% more than B,then B is less than A by [(R/(100+R))*100]% ii)If A is R% less than B,then B is more than A by [(R/(100-R))*100]%