4. The units of an item available for sale during the year were as follows: Jan. 1 Inventory Mar. 4 Purchase 20 units at $65 40 units at $68 25 units at $62 15 units at 560 June 7 Purchase Nov, 15 Purchase There are 50 units of the item in the physical end inventory at December 31. The periodic inventory system is used. Determine the ending inventory cost using FIFO.