i need help understanding this question

Acme Corp. began operations in the fourth quarter of 2020. During the fourth quarter, Acme purchased 500 items of inventory for $20 each ($10,000 total cost) and later an additional 300 items of inventory for $22 each ($6,600 total cost). Later in the fourth quarter, Acme sold 600 items for $30 each, which was the only sale during the quarter. What is Acme's Cost of Goods Sold during 2020? Acme uses the FIFO cost flow assumption. (just enter the number, without any commas or a dollar sign)