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

Inventory

Date Units and Cost

Dec. $13,500$ units at $$21$

Purchases

Date Units and Cost

Dec. $101,750$ units at $$23$

$201,575$ units at $$25$

Sales

Date Units

Dec. $122,450$ units

$142,100$ units

$311,050$ units