How long will it take for the population of a certain country to double if its annual growth rate is 3.9%
2 = 1.039^n
log 2 = n log 1.039
n = 18.1 years
To find out how long it will take for the population of a country to double, we can use the rule of 70. The rule of 70 is a simple formula used to estimate the doubling time of a quantity that grows exponentially over time.
The rule states that the doubling time is approximately equal to 70 divided by the growth rate. In this case, the annual growth rate is 3.9%.
So, to find the doubling time, we divide 70 by the growth rate:
Doubling time = 70 / 3.9 ≈ 17.95
Therefore, it would take approximately 17.95 years for the population of the country to double if its annual growth rate is 3.9%.