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 15 units for $33 each. S 5-11 (Algo) Perpetual: Assigning costs with FIFO LO P1 equired: etermine the costs assigned to the December 31 ending inventory based on the FIFO method