Practice problem one: Shown below is the activity for one of the products of Random Creations January 1 balance, 80 units @ $50 $4,000 Purchases: January 18: 40 units @ $51 January 28: 40 units @ $52 Sales: January 12: 30 units January 22: 30 units January 31: 45 units Require: Calculate the ending inventory and COGS, using Average Cost, FIFO and LIFO under both perpetual and period inventory system