Bonita Industries markets CDs of numerous performing artists. At the beginning of March, Bonita had in beginning inventory $2,500$ CDs with a unit cost of $$6.$ During March, Bonita made the following purchases of CDs$.$

March $5$

$2,150$

@

$$7$

March $21$

$4,800$

@

$$9$

March $13$

$4,000$

@

$$8$

March $26$

$2,150$

@

$$10$

During March $12,000$ units were sold. Bonita uses a periodic inventory system.

whats the average cost?