Solve

Short Answer

Solve:
$$\begin{array} { | l | l | l | l | } \hline \text { Principal } & \text { Rate } & \begin{array} { l } \text { Time (in } \\\text { years) }\end{array} & \begin{array} { l } \text { Simple } \\\text { Interest }\end{array} \\\hline \$ 5,000 & 5 \% & ? & \$ 800 \\\hline\end{array}$$