Madhya Pradesh Police Exam Model Paper 3

Given:
Increase in population for 2 years = 25%
No. of villagers who left in third year = 500
Decrease in population in fourth year = 10%
Population at the end of fourth year = 6750
Concept used:
Indirect method: If 10% increment in number and number becomes a , then original number $=\mathit{a}\times \left(100/110\right).$
Calculation:
At the beginning of fourth year,
$\Rightarrow 6750\times \left(100/90\right)=7500$
At the beginning of third year,
$\Rightarrow 7500+500=8000$
At the beginning of first year,
$\Rightarrow 8000\times \left(100/125\right)\times \left(100/125\right)$
$\Rightarrow 5120$
∴ The population of the village at the beginning of the first year is 5120.