Posted by **abc** on Monday, February 19, 2007 at 10:01pm.

A widget factory has fixed costs of 35 billion dollars and variable costs of 781 million dollars per widget. The revenue (in $ billions) from selling x number of widgets is given by the following for x between 0 and 60.

R(x) = 0.11 (60x - x2)

What is the marginal profit (in $ billions per widget) at production level x = 19 widgets? (Give your answer correct to 3 decimal places.)

$ ____ billion per widget

Write down the cost function C(x) and the revenue function R(x). They have already told you that the R(x) function is

R(x) = 0.11(60 x - x^2)

C(x) = 35 + 0.781 x (in $billions)

The marginal profit is R'(x) - C'(x)

The ' notation denotes a derivative.

R'(x) = 6.6 - 0.22 x

Complete the final steps and substitute x = 19 for the marginal cost of selling one more when x = 19.