A linear cost function is Cx = 5x +250. What is the cost of producing one more item if 50 are currently being produced? What is it if 100 are currently being produced?

Answer 1

C(x) = 5x + 250

The slope (5) is the cost per unit, regardless of whether you're producing 50 or 100. To convince yourself, try computing the following:

C(101) - C(100) = 5(101)+250 - (5(100)+250) = ____?

Try for C(51) - C(50) as well.