Inventory Cost of Goods Sold

Need help with writing a Memo to the manager explaining and detailing a minimum of one element in response to Inventory Cost of Goods Sold. The company uses a perpetual inventory system and the FIFO cost method. Please explain briefly:

1. How to Determine ending inventory and cost of goods sold at the end of the year.

2. How to determine income before income taxes for the year.

3. Discuss financial reporting purposes, and the company uses LIFO (amounts based on a periodic inventory system). Record the year-end adjusting entry for the LIFO reserve.