Question

The population of a town increases at the rate of $20\%$ during the first year and it decreases at the rate of $20\%$ during the second year. If it has $38,400$ inhabitants at present, find the inhabitants two years ago.

• A. $25,000$
• B. $30,000$
• C. $35,000$
• D. $40,000$

Answer 1

The correct option is D $40,000$

Let the population two years ago be = x
According to the question, $38400=1.20\times 0.80\times x$
$x=\frac{38400}{0.96}=40,000$
Hence, population two years ago was $40,000$.