Answer:
4.67 years
Step-by-step explanation:
The future population is calculated by [tex]A=P(1+i)^{n}[/tex] where A is projected population, P is present population, i is interest rate in decimal and n is duration in years.
[tex]84000=42000(1+0.16)^{n}\\n=\frac {log 2}{log 1.16}=4.6701735389888214612132532241097152772246\approx 4.67 years[/tex]
