Three outlets A, B and C are supplied by three suppliers X, Y and Z. The table shows the cost, in pounds, of transporting each unit, the number of units required at each outlet and the number of units available at each supplier.

A B C Supply X 9 11 10 30 Y 10 8 12 50 Z 12 7 8 40 Demand 50 40 30

a) Use the north-west corner method to obtain an initial solution. b) Use the least-cost method to obtain an initial solution. c) Find the total cost of each solution.