Answer:
4811
Step-by-step explanation:
The multiplier in 5 hours is 3900/3000 = 1.3, so we can write the exponential growth function as ...
n(t) = (initial number)·(growth factor)^(t/(time for growth factor))
n(t) = 3000·1.3^(t/5)
Then the number present after 9 hours is ...
n(9) = 3000·(1.3^9/5) ≈ 4811
