Hercules Films is deciding on the price of the video release of its film Bride of the Son of Frankenstein. Marketing estimates that at a price of p dollars, it can sell q = 300,000 − 15,000p copies, but each copy costs $4 to make. What price will give the greatest profit?

Question

STUCK ON THIS PROBLEM PLEASE HELP ME OUT!
THANKS IN ADVANCE :)

Answer 1

revenue = price * demand = pq = p(300000-15000p)
cost for q copies is 4q
profit = revenue-cost

= p(300000-15000p)-4(300000-1500p)
= -15000p^2 + 306,000p - 1,200,000
maximum profit is thus at
p = 306000/30000 = 10.20

Answer 2

Thank you, but i entered in the answer you got (10.20) and it said it was wrong.