3. Calculate COGS and Ending Inventory using a periodic FIFO inventory cost flow system: of Units Cost per Unit 1/1/2018 Beginning Inventory 1/2/2018 Purchase 1/6/2018 Sale 1/11/2018Purchase 1/15/2018 Sale $6 $7 500 300 300 300 200 $10 Cost of Goods Sold: Ending Inventory Balance: 4. Calculate COGS and Ending Inventory using a perpetual LIFO inventory cost flow system: # of Units Cost per Unit 1/1/2018 Beginning Inventory 500 $6 1/2/2018 Purchase $7 1/6/2018 Sale 1/11/2018 Purchase 11/15/2018 Sale 300 300 300 200 $10