Current population = P = 8742
Population after t years = A = 12000
Growth rate = r = 5%
We are to find the number of years it takes the population to grow to 12,000.
So, we can write:
[tex]A=P(1+r)^{t} [/tex]
Using the values, we get:
[tex]12000=8742(1+0.05)^{t} \\ \\
\frac{12000}{8742}= (1.05)^{t} \\ \\
t=6.492[/tex]
This means, it will take 6.492 years for the population to grow to 12,000.