Complete the third column of the following table by calculating the marginal cost per dozen pizzas using the information on total cost. Then complete the final column by calculating the marginal cost per dozen pizzas using the information on variable cost.

Quantity	Total Cost	Marginal Cost	Variable Cost	Marginal Cost
(Dozens of pizzas)	(Dollars)	Using Total Cost	(Dollars)	Using Variable Cost
(Dollars)	(Dollars)
0	280		0
1	320	40
2	350	70
3	380	100
4	420	140
5	470	190
6	530	250