Can someone please help me with this homework question? I got the wrong answer and I want to understand what I did wrong. much appreciated!

378 Problems 8.2A and 8.3A are based on the following Speed World Cycles sells high-performance motorcycles and motocross racers. One of Whrld's most popular models is the Kazomma 900 dirt bike. During the current year, nikes at the following costs. L08-4 PROBLEM 8.3A Alternative Cost Flow Assumptions in a Periodic System Assume that Speed World uses a periodic inventory system. (See the data given before Problem 8.2A.) Instructions a. Compute the cost of goods sold relating to the sale on July 28 and the ending inventory of Kazomma 900 dirt bikes at September 30, using the following cost flow assumptions. 1. Average cost. 2. FIFO. 3. LIFO. Show the number of units and unit costs in each cost layer of the ending inventory. You may determine the cost of goods sold by deducting ending inventory from the cost of goods available for sale