3. Perpetual inventory using weighted average Beginning inventory, purchases, and sales for 30xT are as follows: May 1 Inventory 300 units at $8 175 units 13 Sale 375 units at $10 22 Purchase 29 Sale 280 units Assuming a perpetual inventory system and using the weighted average method, determine (a) the weighted average unit cost after the May 22 purchase, (b) the cost of the merchandise sold on May 29, and (c) the inventory on May 31