## A community for students. Sign up today

Here's the question you clicked on:

## mathcalculus 2 years ago can someone help me where I'm going wrong? :( (1 pt) A producer finds that demand for his commodity obeys a linear demand equation , p+11x=30 where P is in dollars and X in thousands of units. If the cost equation is c(x)=8.8x^2+20x+2.5 , what price should be charged to maximize the profit? The price to maximize the profit is \$ .

• This Question is Closed
1. mathcalculus

i found the price: p=(30-11x)*x

2. mathcalculus

30x-11x^2- (8.8x^2+20x+2.5)

3. mathcalculus

= 10x-19.8x^2-2.5

4. mathcalculus

the i find the derivative: dp/dx and set it to zero.... i got x= .252525

5. mathcalculus

then i tried to plug into c(x) but it's wrong :((

6. mathcalculus

i got 8.05

7. mathcalculus

8. Mertsj

Isn't profit= revenue - cost?

9. mathcalculus

yeah

10. Mertsj

I got 6.87 for the price

11. mathcalculus

how? it says its not correct..

12. Mertsj

price = (30-11x)x

13. mathcalculus

right.

14. Mertsj

So if x = .25, price = (30-11/4).25=6.68

15. Mertsj

All depends on how many significant digits you carry for x

16. mathcalculus

i tried that one too

17. mathcalculus

its wrong.

18. Mertsj

cost per unit is c(x)/x

19. mathcalculus

ok

20. Mertsj

If you want price per unit shouldn't you divide the price by 1000 since x is 1000 units?

21. mathcalculus

howd you get that

22. Mertsj

and X in thousands of units. I read the problem you posted.

23. mathcalculus

yeah can you tell me where i went wrong?

24. Mertsj

Well, I am not sure but I would try dividing the answers we got by 1000 and see if that is the price per unit.

25. mathcalculus

whered you get 1000 from?

26. Mertsj

What does x represent?

27. mathcalculus

the price

28. Mertsj

Read the problem. What does x represent.

29. mathcalculus

thousands in units.

30. Mertsj

So when you got x = .25 that meant .25 thousands of units of 250 units. So when you got 6.87 for the price of x units that was for 1000 units. So each unit should be sold for 7 cents

31. mathcalculus

okay... so i got x= .25 and i times that by 1000...

32. mathcalculus

so whats the correct answer?

33. mathcalculus

im getting it wrong.

34. Mertsj

So if x = .25, price = (30-11/4).25=6.68 for 250 units. 6.68/250=668 cents/250= 3 cents per unit. Try that. How many chances do you get?

35. mathcalculus

huh?

36. Mertsj

I think the part you can't get a handle on is that x is in thousands of units. So if x is 1 that is 1000 units. If x = 2, that is 2000 units. If x = .25 that is 250 units.

37. mathcalculus

right.

38. mathcalculus

i understand that part.

39. Mertsj

What did you get for x?

40. mathcalculus

555003.

41. Mertsj

Well that is not what you posted earlier.

42. mathcalculus

i plugged in 250 into c(x)

43. mathcalculus

i dont know.

44. mathcalculus

whats the answer then?

45. mathcalculus

isn't it .252525 *1000 = x= 252.525

46. Mertsj

I don't know for sure. I wanted you to try 3 cents and I asked you how many chances you get at entering the correct answer and you didn't answer me.

47. mathcalculus

as many times.

48. Mertsj

Did you try 3 cents?

49. mathcalculus

yeah its wrong.

50. Mertsj

I guess I can't help you then. Sorry.

#### Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy