Respuesta :
Since it is given that the population grows by 5% each year, it follows that the Exponential Growth Function is the appropriate function that can be used to model the problem.
The Exponential Growth Function is given by:
[tex]y=a(1+r)^t[/tex]Where
• a is the initial amount.
,• r is the percent of increase in decimal.
,• t is the time.
,• y is the amount after time t.
Since we want when the initial population will triple, substitute y=3a into the equation:
[tex]3a=a(1+r)^t[/tex]Substitute r=5%=0.05 into the equation:
[tex]3a=a(1+0.05)^t[/tex]Solve the resulting equation for t:
[tex]\begin{gathered} 3a=a(1+0.05)^t \\ \Rightarrow a(1+0.05)^t=3a \\ \Rightarrow a(1.05)^t=3a \\ Divide\text{ both sides by a:} \\ \Rightarrow(1.05)^t=3 \\ \text{Take logarithm of both sides:} \\ \Rightarrow\ln (1.05)^t=\ln 3 \\ \Rightarrow t\ln (1.05)=\ln 3 \\ \Rightarrow t=\frac{\ln 3}{\ln (1.05)}\approx22.52\text{ years} \end{gathered}[/tex]The population will triple after about 22.52 years.
