The Manzano Petrochemical Corp. is one of the top growing petrochemical companies based in the Philippines. It has six oil wells in multiple countries and produces 125,000,000 barrels of oil each year. Five refineries in the Philippines work together to process all of this oil. The yearly capacity of each oil well and refinery are shown in the tables below where one unit represents 1,000,000 barrels of oil.

Supply Demand Units Units Oil Well 1 25 Refinery 1 20 Oil Well 2 15 Refinery 2 10 Oil Well 3 20 Refinery 3 20 Oil Well 4 30 Refinery 4 35 Oil Well 5 25 Oil Well 6 10 Refinery 5 40 The company employs freight ships that can carry 1,000,000 barrels to transport the oil from overseas back to the Philippines. The cost of transporting 1,000,000 barrels from oil well to refinery varies according to the distance of the refinery to the oil well. The costs in pesos are shown in the table below. Shipping cost Refinery1 Refinery2 Refinery 3 Refinery 4 Refinery 5 Oil Welli 250000 60000 225000 210000 670000 oil well2 330000 225000 315000 350000 470000 Oil Well 3 110000 340000 370000 370000 540000 Oil Well 225000 600000 390000 335000 230000 oil wells 385000 390000 230000 460000 225000 oil well 6 400000 220000 260000 500000 310000 Create a schedule on how many units of oil should be transported from the oil wells to the refineries on a yearly basis in order to minimize the total cost of transportation. Using North-West Corner method and the stepping stone method, solve for the minimum total transportation cost