must show work

The units of an item available for sale during the year were as follows: There are 50 units of the item in the physical inventory at December 31 The periodic inventory system is used. Assume all units were sold for $150 each. Determine the ending inventory cost, Cost of Merchandise Sold and Gross Profit by (a) the first-in, first-out method, (b) the last- in, first-out method, and (c) the average cost method. Show your work