The company uses the perpetual inventory system for recording its cost of sales. Calculate the Cost of Sales for $14$ December using FIFO method and show this in a inventory cost flow method $-$ perpetual system using the following information: The inventories and purchases for the month of December are as follows:

December $1,$ Beginning inventory: Quantity is $100$ units, cost per unit is $$1\mathrm{.}00.$ December $3,$ Purchases: Quantity is $200$ units, cost per unit is $$1\mathrm{.}30.$ December $7,$ Sales: Sales is $220$ units. December $9,$ Purchases: Quantity is $280$ units, cost per unit is $$1\mathrm{.}80.$ December $14,$ Sales: Sales is $280$ units. December $18,$ Purchases: Quantity is $300$ units, cost per unit is $$2\mathrm{.}00.$ December $21,$ Sales: Sales is $200$ units. December $30,$

Purchases: Quantity is $100$ units, cost per unit is $$2\mathrm{.}20.$

During the month, units were solde for $$3\mathrm{.}50$ per unit.