4. Firm's Costs Your cousin Vinnie owns a painting company with fixed costs of $200 and the following schedule for variable costs:

Quantity	Variable Cost	Average Fixed Cost	Average Variable Cost	Average Total Cost
(Houses Painted per Month)	(Dollars)	(Dollars)	(Dollars)	(Dollars)
1	10	200.00
2	20	100.00
3	40	66.67
4	80	50.00
5	160	40.00
6	320	33.33
7	640	28.57

The efficient scale is

houses.