(c) 5%
Let the rate of increase of population per annum be r%. Then,
22050 = 20000\(\big(1+\frac{r}{100}\big)^2\)
\(\Rightarrow\) \(\frac{22050}{20000}\) = \(\big(1+\frac{r}{100}\big)^2\)
\(\Rightarrow\) \(\frac{441}{400}\) = \(\big(1+\frac{r}{100}\big)^2\) \(\Rightarrow\) \(\big(\frac{21}{20}\big)^2\)= \(\big(1+\frac{r}{100}\big)^2\)
\(\Rightarrow\) 1+ \(\frac{r}{100}\) = \(\frac{21}{20}\) \(\Rightarrow\) \(\frac{r}{100}\) = \(\frac{21}{20}\) - 1 = \(\frac{1}{20}\)
\(\Rightarrow\)r = \(\frac{1}{20}\)x 100 = 5% p.a.
