# Homework Help: Economics MBA profit maximisation toffee

1. Aug 28, 2007

### jackievdberg

[SOLVED] Economics MBA profit maximisation toffee

Hi Guys
I have a total blonde moment here :
The question goes :

I need to determine the profit maximising equilibrium output,price and total profit under 2 conditions
a) firm is monopolist b ) perfect competition ( I have the theory on these )

where a firm Produces output at cost of : C = 50 + 20 X
and sells at price P= 220 - 4 X

I started with X ( being any ) and made my colomns , now I am daft - I cannot get the Total cost , Average cost ext to get to the correct profits ????
Should I have used ( X ) as only 1 extra unit , 2 extra units ext or can I still do 10 units , 20 units?
I confused myself here totally.I would appreciate another few brains.
Thank You Thank You
Jackie

2. Aug 28, 2007

### CRGreathouse

Profit is maximized when the cost to produce an extra unit is equal to the price it is sold at.

3. Aug 28, 2007

### EnumaElish

You can go with 10, 20, but the answer won't be as accurate.

In Excel, just tabulate P and C for X = 1, ..., 55. (Do you see why you don't need to go over 55?)

For Monopoly, calculate profit as revenue - cost. I am assuming you can calculate a revenue from price (P) and quantity (X) at each level of X. Profit should be maximized when the change in revenue is equal to the change in cost for an extra unit. (That's CRGreathouse's intuition applied to a monopoly.)

For perfect competition, find the X at which price equals the additional cost of producing X units instead of X-1 units. Can you see what that additional cost is when you look at the formula for C?

For monopoly, the "exact" solution (in fractional units) necessitates use of calculus (derivatives).

Last edited: Aug 28, 2007
4. Aug 29, 2007

### jackievdberg

Thank you very much.It helped me tremendously. I could see where I went wrong.
I appreciate helpful people like you !
God bless.

5. Sep 16, 2007

### selvgov

Hi

Can you please elaborate on the calculation for perfect competition. I still do not get the additional cost. Thank you so much.

6. Sep 16, 2007

### EnumaElish

Just do the calculation. What is C when X = x? What is C when X = x+1?

7. Sep 17, 2007

### jackievdberg

Thank you again,I managed.
I would need help later on with Quantitative methods.
Can I pose questions as I study the equations ?
My email is jackie@mso.co.za
Thanks for sharing your knowledge to help others !
Jackie

8. Sep 17, 2007

### EnumaElish

You may pose all "homework type" questions in forums "precalc math" or "calc & beyond" (as appropriate).

Any open-ended, discussion-type questions should be posed under the appropriate science forum.

9. Nov 18, 2007

### batlhalefi

what isthe price andtoal profit of a monopolistwhen p=220-4x and cost =50+22x?