Windsor, Inc. had $120$ units in beginning inventory at a total cost of $$15,600.$ The company purchased $240$ units at a total cost of

$$43,200.$ At the end of the year, Windsor had $75$ units in ending inventory.

$($a$)$

Compute the cost of the ending inventory and the cost of goods sold under FIFO, LIFO, and average$-$cost$.$