Perpetual inventory using LIFO

Beginning inventory, purchases, and sales data for prepaid cell phones for December are as follows:

Inventory

Date Units and Cost

Dec. $11,600$ units at $$35$

Purchases

Date Units and Cost

Dec. $10800$ units at $$37$

$20720$ units at $$39$

Sales

Date Units

Dec. $121,120$ units

$14960$ units

$31480$ units