REI sells snowboards. Assume the following information relates to REI's purchases of snowboards during September. During the same month, $105$ snowboards were sold. REl uses a periodic inventory system.

$\backslash$table$[[$Date$,$Explanation,Units,Unit Cost,Total Cost,$],[$Sept$.1,$Inventory,$15,$$$112,$$$1,680,],[$Sept$.12,$Purchases,$45,114,5,130,],[$Sept$.19,$Purchases,$50,116,5,800,],[$Sept$.26,$Purchases,${20}_{?},117,2,340,],[,,$Totals,${130}_{?},,$$$14,{950}_{?}$