Oahu Kiki tracks the number of units purchased and sold thrqughout each accounting period but applies its invertory costing method at the end of each month, as if it uses a periodic invertory system. Assume Oahu Kiki's records show the following for the month of Jarnary, Sales tolaled $260$ units.

$\backslash$table$[[,$Date,Units,Unit cost,Total cost$],[$Beginning Inventory,January $1,220,$$$80,$$$17,600$