Percentage Count


PERCENTAGES :-

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

  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 annul 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 depreciates at the rate of R% per annul, 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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