Answer:
9.0 years
Explanation:
The exponential equation for the population can be written as ...
population = (initial population)(1 +growth rate)^t
p = 24000(1.13^t)
We want this to be 72000, so ...
72000 = 24000(1.13^t)
Dividing by 24000 gives ...
3 = 1.13^t
Taking logs, we have ...
log(3) = t·log(1.13)
log(3)/log(1.13) = t ≈ 8.98
It will take about 9.0 years for the elk population to reach 72,000.