Question

The population of a town increased by $25\%$ annually, If the present population is of crore, then what was the difference between the population $3$ years ago and $2$ years ago?

Answer 1

$Presentpopulation=10000000$

Let old population be $x$

Population one year ago $=(x+x)of25\%$

$\therefore (x+x)of25\%=10000000$

$1.25x=10000000$

$x=8000000$

Population two years ago$=x+xof25$

$\therefore (x+x)of25\%=8000000$

$1.25x=8000000$

$x=6400000$

Population of 3rd year ago$=x+xof25$

$1.25x=6400000$

$x=5120000$

Hence,

Difference between the population 3 years ago and 2 years ago$=6400000–5120000=1280000$