The marginal profit in dollars on Brie cheese sold at a cheese store is given by P'(x) = x(90x^2 + 30x), where x is the amount of cheese sold, in hundreds of pounds. The "profit" is -$60 when no cheese is sold. a) Find the profit function, and b) Find the profit from selling 400 pounds of Brie cheese.

That was incorrect, and now the whole problem has to be redone. :(

The new problem reads as follows: The marginal profit in dollars on Brie cheese sold at a cheese store is given by P'(x) = x(20x^2 + 30x), where x is the amount of cheese sold, in hundreds of pounds. The "profit" is -$70 when no cheese is sold. a) Find the profit function, and b) Find the profit from selling 200 pounds of Brie cheese.

May 7th, 2015

If it's easier, could you possibly do these (or in addition to)?

Find the cost function if the marginal cost function is given by C'(x) = x^(2/5) + 9

Find the demand function for the marginal revenue function. Recall that if no items are sold, the revenue is R'(x) = .03x^2 - .07x + 208

May 7th, 2015

Never mind those, I'm working on them. But I do need the initial one. :/ I apologize.

Neither of them were, actually. When I tried those and one variation, it gave me a new problem after three wrong answers. Now it's the one I re-wrote above. I should have taken note of the answer it gave.

For the initial question, as I first posted it, it was 400 pounds, but with the program we must use for homework, we are given three tries until it gives us a similar example to try to solve. Hence why both parts a and b need to be re-worked.

I do understand why you're questioning it. I saw the methodology and worked it out to the same conclusion. However, the final answer they had was six-thousand-something.

ok then, i wish i was able to understand it much better. i also saw the 2nd question but since i did not get the first one correct, i decided not to take it. i feel happy when i deliver the best answers and satisfy my students