Novak Marine Products began the year with $8$ units of marine floats at a cost of $$11$ each. During the year, it made the following purchases: May $5,34$ units at $$16$; July $16,17$ units at $$21$; and December $7,22$ units at $$25.$ Assume there are $29$ units on hand at the end of the period. Novak uses the periodic system. Determine the cost of goods sold under average cost