An office has five workers, and five tasks have to be performed. Workers differ in efficiency and tasks differ in their intrinsic difficulty. The time each worker would take to complete each task is given in the effectiveness matrix in Table 2. How the tasks should be allocated to each worker so as to minimise the total man-hour?

Table 1

TASKS	WORKERS
	I	II	III	IV	V
A	6	12	3	11	15
B	4	1	7	1	10
C	8	11	10	7	11
D	16	19	12	23	21
E	9	5	7	6	10