Required information Trey Monson starts a merchandising business on December 1 and enters into the following three inventory purchases. Also, on December 15 , Monson sells 23 units for $30 each. Required: Monson uses a perpetual inventory system. Determine the costs assigned to the December 31 ending inventory based on the FIFO method. Requited: Monson uses a perpetual kiventory syntem, Desermine the costs ossigned to the December 31 encing inventary baved an the FiFo merthod