Question

During two years, the population of birds of an island became 7 times more than before. If the first year increase in the population was 40% , what was the percent increase of the second year?

Answer 1

The percent increase of the second year is 400%.

Explanation:

Consider the provided information.

Let the population of birds was x.

After 2 years the population becomes 7 times more than before.

Therefore, after 2 years population is 7x.

In first year increase in the population was 40%.

Population after 1st year = x + 40% of x

Population after 1st year = x + 0.40x

Population after 1st year = 1.4x

The population increase from 1st year to 2nd year is: 7x-1.4x=5.6x

Thus the percentage increase is:

`\% increase=(5.6x)/(1.4x)*100=400\%`

Hence, in second year the population of birds increase by 400%.