Question

The population of a town increases at the rate of 50 per thousand. Its population after 2 years will be 22050. Find its present population.

Answer 1

$$\begin{gathered} \mathrm{Population}\mathrm{after}\mathrm{two}\mathrm{years}=\mathrm{P}{\left(1+\frac{\mathrm{R}}{100}\right)}^{\mathrm{n}} \\ 22,050=\mathrm{P}{\left(1+\frac{50}{1000}\right)}^2 \\ 22,050=\mathrm{P}{\left(1.05\right)}^2 \\ \mathrm{P}=\frac{22,050}{1.1025} \\ =20,000 \\ \mathrm{Thus},\mathrm{the}\mathrm{population}\mathrm{two}\mathrm{years}\mathrm{ago}\mathrm{was}20,000. \end{gathered}$$