[tex]\bf \textit{Amount of Population Growth} \\\\ A=Pe^{rt}\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{initial amount}\dotfill &220000\\ r=rate\to 8.5\%\to \frac{8.5}{100}\dotfill &0.085\\ t=\textit{elapsed time}\dotfill &15\\ \end{cases} \\\\\\ A=220000e^{0.085\cdot 15}\implies A=220000e^{1.275}\implies \stackrel{\textit{rounded up}}{A=787314}[/tex]
without rounding is about 787314.31, which means 787314 people plus 0.31 of another, we can only get 0.31 if we saw off one person, which is not happening, thus the rounding.
