Penn Company uses a periodic inventory system. At the end of the annual accounting period, December 31, 2015, the accounting records provided the following information for product 1: Units Unit Cost Inventory, December 31, 2014 1,880 $ 4 For the year 2015: Purchase, March 21 5,100 6 Purchase, August 1 2,860 7 Inventory, December 31, 2015 4,090 FIFO LIFO AVERAGE COST ending inventory Cost of goods sold