< Perpetual inventory using weighted average Beginning inventory, purchases, and sales for WCS12 are as follows: Oct. 1 Inventory Oct. 13 Sale 320 units at $11 200 units Oct. 22 Purchase 380 units at $12 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.