The Following Units Are Available for Sale During the Year

The following units are available for sale during the year:
$\begin{array}{lll}10 \text { units at } \$ 18 \text { each } & \text { Beginning Inventory } & \text { January } 1 \\30 \text { units at } \$ 20 \text { each } & \text { Purchase } & \text { Apri1 } 3 \\28 \text { units at } \$ 25 \text { each } & \text { Purchase } & \text { August } 31 \\17 \text { units at } \$ 30 \text { each } & \text { Purchase } & \text { September } 29 \\21 \text { units } & \text { Ending Inventory } & \text { December } 31\end{array}$ Determine ending inventory cost by (a) FIFO method, (b) LIFO method, and (c) average cost method.