erpetual inventory using weighted average

Beginning inventory, purchases, and sales for WCS$12$ are as follows:

Oct. $1$ Inventory

$320$ units at $$20$

Oct. $13$ Sale

$200$ units

Oct. $22$ Purchase

$380$ units at $$22$

Oct. $29$ Sale

$300$ units

a$.$ Assuming a perpetual inventory system and using the weighted average method, determine the weighted average unit cost after the October $22$ purchase. Round your answer to two decimal places.

$x$ per unit

b$.$ Assuming a perpetual inventory system and using the weighted average method, determine the cost of goods sold on October $29.$ Round your "average unit cost" to two decimal places.

C$.$ Assuming a perpetual inventory system and using the weighted average method, determine the inventory on October $31.$ Round your "average unit cost" to two decimal places.