Question

The population of city increases at rate proportional to the population at that time if the population of city increases from 20 lacks, the population after 15 years.

Answer 1

Population $\alpha$ time

$\therefore P=kt$

$P_1=k{t}_1$ and $P_2=k{t}_2$

$\therefore \frac{P_1}{t_1}=\frac{P_2}{t_2}$

$\therefore P_1{t}_2=P_2{t}_1$

Let the time now be $1$,

Then, population after $15$ years $=t_2$ be

$20,00,000\times 15=P_2\times 1$

$\therefore P_2=3,00,00,000$.