[tex]\bf ~~~~~~ \textit{Simple Interest Earned}\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &\$54\\
P=\textit{original amount deposited}\to& \$1800\\
r=rate\to r\%\to \frac{r}{100}\\
t=years\to &1
\end{cases}
\\\\\\
54=1800r(1)\implies \cfrac{54}{1800}=r\implies 0.03=r
\\\\\\
r\%=0.03\cdot 100\implies r=\stackrel{\%}{3}[/tex]
