A shop has four machinists to be assigned to four machines. The hourly cost of having each machine operated by each machinist is as follows: MachinistMachine (cost/hr)
A B C D
1 $12 $11 $8 $14
2 $10 $9 $10 $8
3 $14 $8 $7 $11
4 $6 $8 $10 $9

However, because he does not have enough experience, machinist 3 cannot operate machine B.

Required:
a. Determine the optimal assignment and compute total minimum cost.
b. Formulate this problem as a general linear programming model.