The following inventory transactions took place for NPR Corporation for the month of May: Date Event Quantity Cost/Selling Price May 1 Beginning Inventory 1,000 $3.55 May 5 Purchase 6,000 3.10 May 10 Purchase 2,000 3.75 May 15 Sale 3,000 6.00 May 20 Sale 2,000 6.00 May 22 Purchase 5,000 3.45 May 24 Purchase 2,000 3.75 May 25 Sale 7,000 6.00 requirements: Calculate the per unit cost, ending inventory quantity on-hand and ending inventory balance for NPR Corporation, assuming the company uses a perpetual inventory system and the weighted average cost formula