Hello! I am having trouble figuring out how to calculate average cost, which is highlighted in red. How do you find the average cost?

Kirtland Corporation uses a periodic inventory system. At the end of the annual accounting period, December 31, the accounting records for the most popular item in inventory showed the following: Units 350 Unit Cost $6.00 Beginning inventory, January1 Transactions during the year: a. Purchase, January 30 b. Purchase, May 1 c. Sale ($8 each) d. Sale ($8 each 250 410 (110) 2.90 7.00 Required a. Compute the amount of goods available for sale. Answer is complete and correct. 5,695 b. & c. Compute the amount of ending inventory and cost of goods sold at December 31, under Average cost, First-in, first-out, Last-in, first-out and Specific identification inventory costing methods. For Specific identification, assume that the first sale was selected two-fifths from the beginning inventory and three-fifths from the purchase of January 30. Assume that the second sale was selected from the remainder of the beginning inventory, with the balance from the purchase of May 1. (Do not round intermediate calculations. Round "Average Cost and Specific Identification" answers to 2 decimal places.) Answer is complete but not entirely correct. Average F irst-In, First-Out Specific In, First- Cost Ending 1,667.00 1750,500 995.60 4,028.00 S 3,9454,1954,699.40 Cost of goods sold