An office has four workers A, B, C and D, and four tasks have to be performed J1, J2, J3 and J4. Workers differ in efficiency and tasks differ in their intrinsic difficulty. Each job will be assigned to one worker. Time each worker would take to complete each task is given in the effectiveness matrix below. How the tasks should be allocated to each worker to minimize the total overall cost?

	J1	J2	J3	J4
A	16	2	3	7
B	5	13	7	5
C	8	6	5	9
D	3	4	5	11

Hint: 1. Construct the reduced matrix and then the modified matrix to reach the optimal matrix.

2. Decide the optimal assignment, then calculate the optimal (minimum) total cost.