Blue Spruce Distribution markets CDs of numerous performing artists. At the beginning of March, Blue Spruce had in beginning inventory 2,470 CDs with a unit cost of $7. During March, Blue Spruce made the following purchases of CDs. March 5 2,090 $8 March 21 5.110 $10 March 13 3,570 $9 March 26 2,180 @ $11 During March, 12,280 units were sold. Blue Spruce uses a periodic inventory system.