Q&A 9.4 shows that a concert’s profit-maximizing price may exceed the price that allows the concert to sell out. Redraw the figure if the concert requires a large fixed cost (lighting, the stage’s appearance, and so forth). Indicate the profit areas if Ms. Swift sets a price such that 

(a) Marginal revenue equals marginal cost 

(b) The concert sells out. How do we know that the first profit area is greater than the second one?