[tex]~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill &\$67.50\\ P=\textit{original amount deposited}\dotfill & \$450\\ r=rate\to 2.5\%\to \frac{2.5}{100}\dotfill &0.025\\ t=years \end{cases} \\\\\\ 67.50 = (450)(0.025)(t)\implies \cfrac{67.50}{(450)(0.025)}=t\implies 6=t[/tex]