Purrfect Pets uses the perpetual inventory system. At the beginning of the quarter, Purrfect Pets has $38,000 in inventory. During the quarter the company purchases $9,100 of new inventory from a vendor, returned $750 of inventory to the vendor, and took advantage of discounts from the vendor of $280. At the end of the quarter the balance in inventory is $30,500. What is the cost of goods sold?