Final answer:
The annual growth rate of the new trout population is approximately 12.0%.
Step-by-step explanation:
To find the annual growth rate of the trout population, we can use the exponential growth formula:
P = P0ert
where P is the final population, P0 is the initial population, r is the annual growth rate, and t is the number of years.
In this case, we have P = 8,500, P0 = 5,000, and t = 4. Plugging these values into the formula, we can solve for r:
8,500 = 5,000e4r
Divide both sides by 5,000:
1.7 = e4r
Take the natural logarithm of both sides:
ln(1.7) = 4r
Divide both sides by 4:
r ≈ ln(1.7)/4 ≈ 0.120