The population of grew from 9000 to 15000 in 6 years summing

The population of grew from 9,000 to 15,000 in 6 years summing uninhibited exponential what is the expected pop in an additional 4 years?

Solution

Let the population fuction be:
P = Po*e^(k*t)
after 6 years:
15000 = 9000 *e^(k*6)
1.67 = e^(k*6)
0.511 = k*6
k = 0.085

So, the function is:
P = Po*e^(0.085*t)
In additional 4 years that is after 10 years from begining
P = 9000*e^(0.085*10)
= 21086
Answer: 21086