Periodic Inventory by Three Methods Dymac Appliances uses the periodic inventory system. Details regarding the inventory of appllances at January 1 , purchases invoices during the nexe inventory count at December 31 are summarized as follows: Z-1 Determine the cost of the inventory on December 31 by the first-in, first-out method. If the aipntory of a particular model comprises one entien purchase plus a portion of another purchase acquired at' different unit cost, ise a separate ine for each purchase. PQints are in inventory at two different costs, eoter the units PURCHASED MOST RECENTLY first. 1. Determine the cost of the inventory on December 31 by the first-in, first-out method. If the inventory of a particular model comprises one entire purchase plus a portion of another purchase acquired at a different unit cost, use a separ purchase. If units are in inventory at two different costs, enter the units PURCHASED MOST RECENTLY first. If the inventory of a particular model comprises one entire purchase 3. Determine the cost of the Inventory on December 31 by the weighte