Concord Distribution markets CDs of numerous performing artists. At the beginning of March, Concord had in beginning inventory 4,500 CDs with a unit cost of $6. During March, Concord made the following purchases of CDs. March 5 5,625 @ $7 March 21 8,750 @ $9 March 13 7,875 @ $8 March 26 7,000 @ $10 During March 25,000 units were sold. Concord uses a periodic inventory system.