Question

The present population of a village is $130,000$. If the population increase each year by $4$% of what it had been at the beginnning of each year, then the population of the village after four years will be $x$ . Find the sum of the digits of $x$.

Answer 1

$P_0=130,000$ ,
$R=4$%,
$n=4$
If the population after 4 years is P,then
$P=P_0\times {(1+\frac{R}{100})}^n$
$=130000{(1+\frac{4}{100})}^4$

$=130000\times \frac{104}{100}\times \frac{104}{100}\times \frac{104}{100}\times \frac{104}{100}$
=$152082$
Population at the end of 4 years = $152082$

Hence, the sum of digits $=1+5+2+0+8+2=18$