[tex]\bf ~~~~~~ \textit{Simple Interest Earned}\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &\$150\\
P=\textit{original amount deposited}\to& \$2000\\
r=rate\to r\%\to \frac{r}{100}\\
t=years\to &3
\end{cases}
\\\\\\
150=2000\cdot r\cdot 3\implies \cfrac{150}{2000\cdot 3}=r\implies 0.025=r
\\\\\\
r\%=0.025\cdot 100\implies r=\stackrel{\%}{2.5}[/tex]