### Concepts on Percentage:

- Percent means for every 100So, when percent is calculated for any value, it means that we calculate the value for every 100 of the reference value.
- percent is denoted by the symbol %. For example, x percent is denoted by x%
- x% = x/100, e.g.: 25%=25/100=1/4
- To express x/y as a percent, we have x/y=(x/y×100)%Example: 1/4=(1/4×100)%=25%
- If the price of a commodity increases by R%, the reduction in consumption so as not to increase the expenditure = [R/(100+R)×100]%
- If the price of a commodity decreases by R%, the increase in consumption so as not to decrease the expenditure = [R/(100−R)×100]%
- If the population of a town = P and it increases at the rate of R% per annum, then Population after n years = P(1+R/100)
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- If the population of a town = P and it increases at the rate of R% per annum, then Population before n years = P/(1+R/100)
^{n} - If the present value of a machine = P and it depreciates at the rate of R% per annum, Then Value of the machine after n years = P(1−R/100)
^{n} - If the present value of a machine = P and it depreciates at the rate of R% per annum, Then Value of the machine before n years = P/(1−R/100)
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