Question

The population of a town increases by $10\%$ annually. If the present population is $22000$, find its population a year ago.

Answer 1

Let the population of the town one year ago $=x$
Now, it is given that population of the town increases by $10\%$ Annually.
Present population $=x+10\%$ of $x$
$=x+\frac{10}{100}\times x$
$=x+\frac{x}{10}$
$=\frac{10x+x}{10}$
$=\frac{11x}{10}$
But present population of the town $=22000$
So, $\frac{11x}{10}=22000$
$11x=220000$
$\Rightarrow x=\frac{220000}{11}$
$\Rightarrow x=20000$
So, population of the town $1$ year ago $=20000$