nancy grant is the owner of coal bank hollow recycling, a company that specialized in collecting and recycling paper products. nancy's company uses two different recycling processes to convert newspaper, mixed paper, white office paper, and cardboard into paper pulp. the amount of paper pulp extracted from the recyclable materials and the cost of extracting the pulp differs depending on which recycling process used. the paper pulp produced from each recycling process also has different yields for the final products. nancy currently has 70 tons of newspaper, 50 tons of mixed paper, 30 tons of white office paper, and 40 tons of cardboard. she has a contract to produce 60 tons of newsprint pulp, 40 tons of packaging paper pulp, and 50 tons of print stock pulp. what is the most cost-efficient way to meet the obligations