[tex]\bf \qquad \textit{Simple Interest Earned}\\\\
I = Prt\qquad
\begin{cases}
I=\textit{interest earned}\to &800\\
P=\textit{original amount deposited}\to& \$1,000\\
r=rate\\
t=years\to &10
\end{cases}[/tex]
solve for "r",
you'll get a decimal amount, just multiply it by 100, to get the percentage figure
