Need help with Calculus,
When the admission price for a baseball game was $5 per ticket, 40,000 tickets were sold. When the price was raised to $6, only 35,000 tickets were sold. Assume that the demand function is linear and that the variable and fixed costs for the ball park owners are $0.10 and $75,000 respectively.

(a) Find the profit P as a function of x, the number of tickets sold.

Find the marginal profits when 20,000 tickets were sold and when 40,000 tickets were sold.

Question

Need help with Calculus, 
When the admission price for a baseball game was $5 per ticket, 40,000 tickets were sold. When the price was raised to $6, only 35,000 tickets were sold. Assume that the demand function is linear and that the variable and fixed costs for the ball park owners are $0.10 and $75,000 respectively.

(a) Find the profit P as a function of x, the number of tickets sold.

Find the marginal profits when 20,000 tickets were sold and when 40,000 tickets were sold.

anonymous · Answer

P(x)=((x-40,000)*((5-6)/(40,000-35,000))+5)*x-(75,000+.1*x)
P(x)=price*quantity-cost

anonymous · Answer

(x-40,000)*((5-6)/(40,000-35,000))+5 is the price, written in point slope form

anonymous · Answer

Ok cause what i got was (-1/5000)x^2+10.9x-75000