Using an exponential function, it is found that:
- For Country A, the doubling time is of 43 years.
- For Country B, the growth rate is of 1.9% per year.
<h3>What is the exponential function for population growth?</h3>
The exponential function for population growth is given as follows:

In which:
- P(t) is the population after t years.
- P(0) is the initial population.
- k is the exponential growth rate, as a decimal.
For Country A, we have that k = 0.016. The doubling time is t for which P(t) = 2P(0), hence:






t = 43 years.
For Country B, P(36) = 2P(0), hence we have to solve for k to find the growth rate.






k = 0.019.
For Country B, the growth rate is of 1.9% per year.
More can be learned about exponential functions at brainly.com/question/25537936
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