Perpetual inventory using weighted average Beginning inventory, purchases, and sales for WCS12 are as follows: Oct. 1 Inventory 320 units at $20 Oct. 13 Sale 200 units Oct. 22 Purchase 380 units at $22 Oct. 29 Sale 300 units a. Assuming a perpetual inventory system and using the weighted average method, determine the weighted average unit cost after the October 22 purchase. Round your answer to two decimal places. per unit b. Assuming a perpetual inventory system and using the weighted average method, determine the cost of goods sold on October 29. Round your "average unit cost" to two decimal places. c. Assuming a perpetual inventory system and using the weighted average method, determine the inventory on October 31. Round your "average unit cost" to two decimal places.