Cowles Corporation. Inc. makes and sells a single product. Product R. Three yards of Material K are needed to make one unit of Product R. Budgeted production of Product R for the next five months is as follows: The company wants to maintain monthly ending inventories of Material K equal to 30% of the following month's production needs. On July 31. this requirement was not met because only 3.500 yards of Material K were on hand. The cost of Material K is $0.80 per yard. The company wants to prepare a Direct Materials Purchase Budget for the rest of the year. The desired ending inventory of Material K for September is