do not use software,thank you.

1. A concrete company transport concrete from the plants to three constructions side. The supply capacities of the three plants, the demand requirement at the three sites, and the transportation cost per on are as follows: Construction Side Plant Supply A B C X 8 5 6 120 Y 15 10 12 80 Z 3 9 10 80 Demand (tons) 150 70 60 280 Determine the initial solution to this problem using North-West Corner Approach and minimum cells cost method