periodic inventory by three methods the units of an item available for sale during the year were as follows: date line item description units and cost jan. 1 inventory 5,500 units at $4 feb. 17 purchase 6,400 units at $6 july 21 purchase 6,000 units at $8 nov. 23 purchase 2,100 units at $10 there are 1,500 units of the item in the physical inventory at december 31. the periodic inventory system is used. a. determine the inventory cost by the first-in, first-out method. fill in the blank 1 of 3$ b. determine the inventory cost by the last-in, first-out method. fill in the blank 2 of 3$ c. determine the inventory cost by the weighted average cost method. round average unit cost to two decimal places. fill in the blank 3 of 3$