It would take 26 years.
The equation will be in the form y = a(1+r)ˣ, where a is the initial population, r is the growth rate as a decimal number, and x is the amount of time. Using our information we have
y = 18450(1+0.027)ˣ = 18450(1.027)ˣ
We want the population to be doubled; 18450*2 = 36900:
36900 = 18450(1.027)ˣ
Divide both sides by 18450:
36900/18450 = 18450(1.027)ˣ/18450
2 = 1.027ˣ
Using logarithms, we have
[tex]\log_{1.027}2=x
\\
\\x=26.017[/tex]
