Question

Population of a town increases at a certain rate per cent per annum. Present population of the town is 3600 and in 5 years’ time it becomes 4800. How much will it be in 10 years time ?

• A. 5000
• B. 6000
• C. 6400
• D. 7000

Answer 1

The correct option is C 6400

Let rate of increase in population $=r\%p.a$
Then $4800=3600{(1+\frac{r}{100})}^5$
$\therefore {(1+\frac{r}{100})}^5=\frac{4800}{3600}=\frac{4}{3}$

Population in the next 5 years will become
$4800{(1+\frac{r}{100})}^5$
$4800\times \frac{4}{3}=6400$