Respuesta :

[tex] \bf ~~~~~~ \textit{Simple Interest Earned}
\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &\$320\\
P=\textit{original amount deposited}\to& \$4000\\
r=rate\to r\%\to \frac{r}{100}\\
t=years\to &2
\end{cases}
\\\\\\
320=4000r(2)\implies \cfrac{320}{4000(2)}=r\implies \cfrac{1}{25}=r\implies 0.04=r
\\\\\\
r\%=0.04\cdot 100\implies r=\stackrel{\%}{4} [/tex]