Trey Monson starts a merchandising business on December 1 and enters into the following three inventory purchases. Monson uses a perpetual inventory system. Also, on December 15 , Monson sells 27 units for $20 each. 2S 5-16A (Algo) Perpetual: Inventory costing with LIFO LO P1 etermine the costs assigned to ending inventory when costs are assigned based on the LIFO method