3. The beginning inventory and purchases of an item for the period were as follows: Beginning inventory First purchase Second purchase Third purchase 6 units at $70 each 10 units at $75 each 18 units at $80 each 10 units at $90 each the periodic system, and there were 15 units in the inventory at the end of the period. Deter- t-in, first-out (b) last-in, first-out; () average cost. Do not round your intermediate calcula- st ste5 units in the inventory by each of the following methods, presenting details of your com- Round your final answer to two decimal places