Answer:
$16,000
Step-by-step explanation:
Revenue is the product of price and the number sold. Using the given relation for number sold, the revenue as a function of price is ...
R(p) = p(-40p +1600) = -40p(p -40)
This is the equation of a quadratic that opens downward and has zeros at p=0 and p=40. The vertex is halfway between those zeros, at p=20. The revenue at this price is ...
R(20) = -40·20(20 -40) = 16,000 . . . . dollars