Question

The population of a certain city was 72000 on the last day of the year 1998. During next year it increased by $7\%$ but due to an epidemic it decreased by $10\%$ in the following year. What was its population at the end of the year 2000?

Answer 1

On the last day of 1998,
Population of a town = 72000
In the first year, increase $=7\%$
In the second year, decrease $=10\%$
$\therefore$ Population in the last day of 2000
$=72000(1+\frac{7}{100})(1-\frac{10}{100})$
$=72000\times \frac{107}{100}\times \frac{9}{10}=69336$