Your Weekly Cost (In Dollars) to Manufacture X Cars and Y

Short Answer

Your weekly cost (in dollars) to manufacture x cars and y trucks is given by
​ $C ( x , y ) = 210,000 + 5,200 x + 3,400 y - 20 x y$ ​
Compute the marginal cost of manufacturing cars at a production level of 14 cars and 13 trucks.
​
$ __________