3. Based on the 2021 annual report of Amazon.com: a) What is the inventory turns ratio? In your calculation, make sure you use the average inventory, and state your answer with two decimal places. b) Based on the average inventory in part a, how many days of supply does that represent? c) If the cost of carrying inventory is 20% of the average inventory, what is the annual savings if inventory turns increases by 50% ? 4. Assume the following transactions have occurred regarding a specific SKU in 2022 : - Ending inventory in 2021 of 100 units valued at $1,175. - January 15 , purchased 1000 units at $12.00 per unit - January 31 , sold 450 units at $15.50 per unit - February 19, sold 120 units at $15.50 per unit - March 3, purchased 500 units at $13.00 per unit - March 25, sold 500 units at $16.00 per unit - April 16, sold 250 units at $16.50 per unit - May 20, sold 80 units at $17.00 per unit - June 6, purchased 1000 units at $13.50 per unit - July 13 , sold 800 units at $16.00 per unit - August 25, purchased 1200 units at $14.00 per unit - October 17, sold 950 units at $17.00 per unit Determine the ending inventory and cost of goods sold using the three methods of inventory valuation: FIFO, LIFO, and weighted average method