The units of an item available for sale during the year were as follows: Date Line Item Description Units and Cost Jan. 10 Inventory 27 units at $90 Feb. 27 Purchase 54 units at $98 July 11 Purchase 63 units at $106 Nov. 13 Purchase 36 units at $115 There are 50 units of the item in the physical inventory at December 31. The periodic inventory system is used.