REI sells snowboards. Assume the following information relates to REI's purchases of snowboards during September. During the same month, 107 snowboards were sold. REI uses a periodic inventory system. Date Explanation Units Unit Cost Total Cost Sept. 1 Inventory 13 $117 $1,521 Sept. 12 Purchases 46 120 5,520 Sept. 19 Purchases 60 121 7,260 Sept. 26 Purchases 21 122 2,562 Totals 140 $16,863