\begin{tabular}{|c|l|c|c|} \hline Date & \multicolumn{1}{|c|}{ Blankets } & Units & Cost \\ \hline May 3 & Purchase & 5 & $20 \\ \hline 10 & Sale & 3 & \\ \hline 17 & Purchase & 10 & 24 \\ \hline 20 & Sale & 6 & \\ \hline 23 & Sale & 3 & \\ \hline 30 & Purchase & 10 & 30 \\ \hline \end{tabular}