Based on Glassey and Gupta (1978). A paper recycling plant processes box board, tissue paper, news-print, and book paper into pulp that can be used to produce three grades of recycled paper. The prices per ton and the pulp contents of the four inputs are shown in the file P04_126.xlsx. Two methods, de-inking and asphalt dispersion, can be used to process the four inputs into pulp. It costs $20 to de-ink a ton of any input. The process of de-inking removes 10% of the input’s pulp, leaving 90% of the original pulp. It costs $15 to apply asphalt dispersion to a ton of material. The asphalt dispersion process removes 20% of the input’s pulp. At most, 3000 tons of input can be run through the asphalt dispersion process or the de-inking process. Grade 1 paper can be produced only with newsprint or book paper pulp; grade 2 paper only with book paper, tissue paper, or box board pulp; and grade 3 paper only with newsprint, tissue paper, or box board pulp. To meet its current demands, the company needs 500 tons of pulp for grade 1 paper, 500 tons of pulp for grade 2 paper, and 600 tons of pulp for grade 3 paper. Determine how to minimize the cost of meeting the demands for pulp.