Question

an insect population grows at a rate of 25% per year.if its initial population is 4.2 million what will be its population in three year?

Answer 1

The population after 3 years would be 8.20 millions.

Step-by-step explanation:

Given,

Initial population = I = 4.2 million

Growing rate = r = 25%

If the initial population and growing rate is given, the formula to calculate the population (x) after n years would be:

$x = I * (1 + \frac{r}{100} )^{n}$

By putting the values in the equation, we get

$x = 4.2 * (1 + \frac{25}{100} )^{n}$

The population after 1st year (x1) would be

$x1 = 4.2 * (1 + \frac{25}{100} )^{1}$

x1 = 5.25 million

Similarly,

$x2 = 4.2 * (1 + \frac{25}{100} )^{2}$

x2 = 6.56 million

$x3 = 4.2 * (1 + \frac{25}{100} )^{3}$

x3 = 8.20 million

Hence, the population after 3 years would be 8.20 millions.

But, if you are asking about the total population at that time. It would be

I + x1 + x2 + x3 = 24.21 million