Results on population

Formula's on result of population are very important when we have to calculate the population n years after or n years before,

Let the population of a town be P now and suppose it increases at the rate of R% per annum, then
$$\begin{aligned} 1. & \text{Population after n years =}P\left(1+\frac{R}{100}\right)^n \\ 2.& \text{Population before n years =} \frac{P}{\left(1+\frac{R}{100}\right)^n} \\ \end{aligned}$$