Respuesta :
[tex]\bf ~~~~~~ \textit{Simple Interest Earned}\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &\$21600\\
P=\textit{original amount deposited}\to& \$30000\\
r=rate\to 6\%\to \frac{6}{100}\to &0.06\\
t=years
\end{cases}
\\\\\\
21600=(30000)(0.06)t\implies \cfrac{21600}{(30000)(0.06)}=t\implies 12=t[/tex]