Periodic inventory using FIFO, LIFO, and weighted average cost methods

The units of an item available for sale during the year were as follows:

There are $20$ units of the item in the physical inventory at December $31.$ The periodic inventory system is used. Determine the inventory cost using the $($a$)$ first$-$in$,$ first$-$out $($FIFO$)$ method; $($b$)$ last$-$in$,$ first$-$out $($LIFO$)$ method; and $($c$)$ weighted average cost method $($round per$-$unit cost to two decimal places and your final answer to the nearest whole dollar$).$

a$.$ First$-$in$,$ first$-$out $($FIFO$)$ method

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b$.$ Last$-$in$,$ first$-$out $($LIFO$)$ method

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c$.$ Weighted average cost method

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