We are given that a city has a population of 136000 in 1992 and a growth rate of 1.7% per year.
Part a) An exponential function that models the exponential growth is given by:
[tex]P=P_0e^{rt}[/tex]Where
[tex]\begin{gathered} P_0=\text{ initial population} \\ r=\text{ growth rate in decimal form} \\ t=\text{ time} \end{gathered}[/tex]The growth rate in decimal form is the following:
[tex]r=\frac{1.7}{100}=0.017[/tex]Now we substitute the values and we get:
[tex]P=136000e^{0.017t}[/tex]Part b) For the year 2005 there are 13 years, therefore, we substitute in the equation the values t = 13:
[tex]P=136000e^{(0.017)(13)}[/tex]Solving the operations we get:
[tex]P=169636\approx170000[/tex]Therefore, the population in 2005 is approximately 170000.