Shamrock, Inc. uses a periodic inventory system reports the following for the month of June. Date Explanation Units Unit Cost Total Cost June 1 Inventory 120 $4 $480 12 Purchases 360 5 1,800 23 Purchases 170 6 1,020 30 Inventory 190 A sale of 400 units occurred on June 15 for a selling price of $9 and a sale of 60 units on June 27 for $10. (a) Calculate the average cost per unit, using a perpetual inventory system. (Round Intermediate calculations to o decimal places, e.g. 5.250 and final answers to 3 decimal places, e.g. 5.125.) June 1 $ June 12 $ June 15 $ June 23 $ June 27 $