Ferris Company began January with 4,000 units of its principal product. The cost of each unit is $6. Merchandise transactions for the month of January are as follows: Date of Purchase Jan. 10 Jan. 18 Totals Units 3,000 4,000 7,000 Purchases Unit Cost* $ 7 8 Total Cost $21,000 32,000 53,000 * Includes purchase price and cost of freight. Sales Date of Sale Jan. 5 Jan. 12 Jan. 20 Total Units 2,000 1,000 3,000 6,000 5,000 units were on hand at the end of the month. 4. Calculate January's ending inventory and cost of goods sold for the month using Average cost, periodic system