LIFO & Average Cost periodic inventory methods.

The Rock Shop shows the following data related to an item of inventory:

Inventory, January $1100$ units @ $$5\mathrm{.}00$

Purchase, January $9300$ units @ $$5\mathrm{.}40$

Purchase, January $1970$ units @ $$6\mathrm{.}00$

Inventory, January $31120$ units

Instructions

$($a$)$ What value should be assigned to COGS and ending inventory using LIFO?

$($b$)$ What value should be assigned to COGS and ending inventory under Average Cost?