The beginning inventory and purchases of an item for the period were as follows: March 3 Beginning inventory March 11 First purchase March 14 Sale March 21 Second purchase March 25 Sale 12 units at $15 each 13 units at $17 each 18 units 9 units at $20 each 10 units Determine the cost of the ending inventory of 19 units in the inventory by each of the following methods, presenting details of your computations for: (a) first-in, first-out; (b) last-in, first-out; (c) average cost under both periodic and perpetual inventory systems