13. The Ace Machine Company is considering using a priority scheduling rule in its fabrication shop and must decide whether to use: the critical ratio rule, the order slack rule, the shortest operation next rule, or the slack per operation rule. Exhibit A shows the company’s current inventory and shop status.

a. State the formula for calculating the priority index for each of the sequencing rules given previously.

b. Compute the scheduling priority for each order in Exhibit A, for all four sequencing rules.