Oahu Kiki tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each month, as if it uses a periodic inventory system. Assume Oahu Kiki's records show the following for the month of January. Sales totaled $270$ units.

$\backslash$table$[[,$Date,Units,Unit Cost,Total Cost$],[$Beginning Inventory,January $1,140,$$$75,$$$10,500$