[tex]\bf ~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill&\$75\\ P=\textit{original amount deposited}\dotfill & \$450\\ r=rate\to r\%\to \frac{r}{100}\\ t=years\dotfill &3 \end{cases} \\\\\\ 75=(450)r(3)\implies \cfrac{75}{(450)(3)}=r\implies \cfrac{1}{18}=r\implies 0.0\overline{55}=r \\\\\\ \stackrel{\textit{converting it to percentage}}{r\% \approx 0.055\cdot 100}\implies r\approx \stackrel{\%}{5.5}[/tex]
