Question

The population of a town increases annually by $25\%$ if the preset population is $1$ crore, then what was the difference between the population three years ago and two years ago?

• A. $25,00,000$
• B. $12,80,000$
• C. $15,60,000$
• D. None of these

Answer 1

Answer: (B)

$12,80,000$

Given that,

Population increases annually by $25\%$

Let population $3$ years ago be $x$

$\Rightarrow$ Population two years ago was $\frac{125}{100}x$

Population last year was $\frac{125\times 125}{10000}x$

Population this year is $\frac{125\times 125\times 125}{1000000}x=10000000$

$\Rightarrow$ Population three years ago was $x=5120000$

$\therefore$ Difference between population three years ago and two years ago $=25\%$ of $x$

$=1280000$