Addison, Inc. uses a perpetual inventory system. Below is information about one inventory item for the month of September. Use this information to answer the questions that follow. Sep. 1 Inventory 20 units at $20 4 Sold 10 units I 10 Purchased 30 units at $25 17 Sold 20 units 30 Purchased 10 units at $30 5. If Addison uses FIFO, the September 30 inventory is a. $800 b. $650