Anne Sugar makes large ceramic pots for use in outdoor landscaping. She currently has two models, one square and the other round. Because of the size of Anne's creations, only one pot can be fired in the kiln at a time. Information about each model follows:

SquareRoundSales price$70$90Variable cost$15$20Firing time2.5hours3.5hours

Suppose that Anne has developed a rectangular, medium-size ceramic pot. It requires four hours of kiln time; however, two medium-size pots can fit in the kiln at once. The medium-size pots would sell for $60 each and have variable cost of $10 per pot.

If Anne has only 40 hours of firing time available per week, what is the maximum amount of contribution margin she can earn per week?