Find the marginal revenue when 30 items are sold

Question

Suppose that the revenue (in dollars) from selling x items is given by r'(x)=-0.1x^3+525x

Answer 1

r'(x) = marginal revenue

r'(30) = -0.1(30)^2+525(30) = -90+ 15750 = 15660

but you have an ambiguity in the problem

you state revenue is given by r'(x) so, if total revenue =-.1(x^2)+525x

then marginal revenue = -.2x +525 and at x=30, that would = -6+525 = 519

but "r'(x)" usually means the derivative of r(x) where r(x) is the total revenue function.

It's unclear which answer you want. that ' might just be a typo, or maybe you meant to write marginal revenue instead of revenue