Steinmetz furniture purchases 2 products for resale: big shelves (B) and medium shelves (M). Every big shelf costs $100 and needs 100 cubic feet of storage space, and every medium shelf costs $50 and needs 80 cubic feet of storage space. Company has $25000 to invest in shelves week, and warehouse has 18000 cubic feet available for storage. Profit for every big shelf is $85 and for every medium shelf is $75. To maximize profit, find how many big shelves (B) and find how many medium shelves (M) must be bought?