Answer:
16.5 years
Step-by-step explanation:
The exponential growth model usually applied to interest is also useful in this type of problem. Here,
initial population: 20,000
final population: 35,300
Annual interest rate: 3.5% <=> 0.035
Then A = P(1 + r)^t becomes
ln A = ln P + t*ln 1.035, so that
ln A - ln P 0.5682
t = ------------------ = -------------- = 16.5 years
ln 1.035 0.0344
