scheduled for the routing machine: \begin{tabular}{cccc} \hline Order & \begin{tabular}{c} Time Since Order \\ Arrived (hours ago) \end{tabular} & \begin{tabular}{c} Estimated Machine \\ Time (hours) \end{tabular} & \begin{tabular}{c} Due Date \\ (hours from now) \end{tabular} \\ \hline 1 & 3 & 15 & 18 \\ 2 & 1 & 9 & 20 \\ 3 & 0 & 7 & 21 \\ 4 & 6 & 10 & 12 \\ 5 & 5 & 3 & 8 \\ \hline \end{tabular} Using the FCFS (first come, first served) decision rule for sequencing the orders, the order is: \begin{tabular}{l|ccccc} \hline Sequence & 1 & 2 & 3 & 4 & 5 \\ \hline Order & & & & & \\ \hline \end{tabular}