9514 1404 393
Answer:
about 15.5%
Explanation:
The number of foxes in the forest can be modeled by the exponential equation ...
f = a·b^t
where a is the initial number, and b is the growth factor per year for t years. The growth factor is 1 more than the growth rate (r), so we can put numbers in this formula to get ...
40 = 30·(1 +r)^2
4/3 = (1 +r)^2 . . . . . . divide by 30
1 +r = √(4/3) . . . . . . take the square root
r = √(4/3) -1 ≈ 0.1547 ≈ 15.5%
The annual percentage growth in the fox population is about 15.5%.