23 In a job shop operation, four jobs can be performed on any of four machines. The hours required for each job on each machine are presented in the following table:

MACHINE JOB W X Y Z A 16 14 10 13 B 15 13 12 12 C 12 12 9 11 D 18 16 14 16 The plant supervisor would like to assign jobs so that total time is minimized. Use the assignment model to find the best solution.