The Carter Caterer Company must have the following number of clean napkins available at the beginning of each of the next four days: day 1, 1500; day 2, 1200; day 3, 1800; day 4, 600. After being used, a napkin can be cleaned by one of two methods: fast service or slow service. Fast service costs 50 cents per napkin, and a napkin cleaned via fast service is available for use the day after it is last used. Slow service costs 30 cents per napkin, and these napkins can be reused two days after they are last used. New napkins can be purchased for a cost of 95 cents per napkin. Determine how to minimize the cost of meeting the demand for napkins for the next four days. Assume that we do not have any napkins on hand. The objective of this problem is to model this as a network flow model.