Trey Monson starts a merchandising business on December 1 and enters into the following three inventory purchases, Also, on December 15 , Monson sells 30 units for $35 each. QS 6-10 Perpetual: Assigning costs with FIFO LO P1 Required: Monson uses a perpetual inventory system. Determine the costs assigned to the December 31 ending inventory based on the FiFO method. Perpetual FIFO