Perpetual Inventory Using Weighted Average Beginning inventory, purchases, and sales for Meta-81 are as follows: July 1 Inventory 100 units at $400 12 Sale 70 units 23 Purchase 120 units at $450 26 Sale 110 units a. Assuming a perpetual inventory system and using the weighted average method, determine the weighted average unit cost after the July 23 purchase. per unit b. Assuming a perpetual inventory system and using the weighted average method, determine the cost of the merchandise sold on July 26. c. Assuming a perpetual inventory system and using the weighted average method, determine the inventory on July 31,