In a job shop operation, four jobs may be performed on any of four machines. The hours required for each job on each machine are presented in the following table. The plant supervisor would like to assign jobs so that total time is minimized. Find the best solution. Which assignments should be made?

MACHINE

JOB

W

X

Y

Z

A12

10

14

16

13

A15

12

13

15

12

B2

9

12

12

11

B9

14

16

18

16