Question

The population of a town increases at the rate of 40 per thousand annually. If the present population be 175760, what was the population three years ago?

Answer 1

Present population (A) = 175760
Increase rate = 40 per 1000
Period = 3 years
Let 3 years ago, population was = P
$\therefore A=P{(1+\frac{40}{1000})}^3$
$=175760\times \frac{25}{26}\times \frac{25}{26}\times \frac{25}{26}=156250$
$\therefore$ 3 years ago, population was 156250.