A machine operator processes 5 types of items on his machines each week and must choose a sequence for them. The setup cost per change depends on the item presently on the machine and the setup to be made according to the following table.

(To change to Job)

(To change from Job)

A B C D E A ∞ 4 7 3 4 B 4 ∞ 6 3 4 C 7 6 ∞ 7 5 D 3 3 7 ∞ 7 E 4 4 5 7 ∞