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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]%
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