[tex]\bf ~~~~~~ \textit{Simple Interest Earned}\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &\$306\\
P=\textit{original amount deposited}\to& \$1700\\
r=rate\to 3\%\to \frac{3}{100}\to &0.03\\
t=years
\end{cases}
\\\\\\
306=1700\cdot 0.03\cdot t\implies 306=51t\implies \cfrac{306}{51}=t[/tex]