ANSWER
EXPLANATION
We want to find the number of years that it will take the population to double.
To do this, we have to apply the exponential growth function:
where y = final value
a = initial value
r = rate of growth
t = time (in years)
For the population to double, it means that the final value must be 2 times the initial value:
Substitute the given values into the function above:
To solve further, convert the function from an exponential function to a logarithmic function as follows:
Solve for t:
It will take 9 years for the population to double.