[tex]~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill&\$200\\ P=\textit{original amount deposited}\dotfill & \$850\\ r=rate\to 7\%\to \frac{7}{100}\dotfill &0.07\\ t=years \end{cases} \\\\\\ 200=850(0.07)t\implies \cfrac{200}{850(0.07)}=t\implies \stackrel{\textit{about 3 years, 4 months and 10 days}}{3.36\approx t}[/tex]
