3. Columns 4 to 7 indicate, for each item, the purchase unit which is the size of the shipping container (ground beef comes in 10-pound bag), number of purchase units (there are six 10-pound bags in a purchase unit of ground beef), cost per unit (a 10-pound bag of ground beef costs $28.50-or $2.85 per pound), and total cost of the item (six 10-pound bags of ground beef at $28.50 equals $171).