A magician performs in a hall with a seating capacity of 1,000 spectators. With ticket prices set at $47, the average attendance has been 640 spectators. A marketing survey shows that for each dollar the ticket price is lowered, the average attendance increases by 20.
Which of the following functions models the revenue in terms of ticket price (P)?
a) Revenue(P) = (47 - P) ⋅ (640 + 20P)
b) Revenue(P) = (47 + P) ⋅ (640 - 20P)
c) Revenue(P) = (47 - P) ⋅ (640 - 20P)
d) Revenue(P) = (47 + P) ⋅ (640 + 20P)
