# Calculus (Help)

posted by
**Confused**
.

Can you please help me with this problem? I asked earlier, but nobody was able to help me... I've been working on it for about an hour now.

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 - x^2)

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

Please help me, I would greatly appreciate this!

Take the derivative of R(x) to get marginal revenue. Solve that for dR(x)/dx for x=19

dR/dx= .11(60-2x)=.11(60-2(19) )

check my thinking.