Hello, I have a very brief conceptual question: Given two firms, let's say for instance that P = 200 - 10Q, where Q is the combination of firm A & B. Would the marginal revenue be solved by multiplying one of the individual firm's quantity by 2. That is, the marginal revenue for firm A would be solved from: 0 = 200 - 10q(b) - 20q(a) Given that this is true, is this monopolistic-like solution only possible in such a theoretical oligopolistic duopoly because each firm's output is still dependent upon the other's output? I understand that a marginal revenue curve having twice the slope as the price curve is true only for monopoly situations, and therefore I am wondering what is the theory behind why it is also applicable in a duopoly. Also, given that this is true, is it also true in oligopolies with more than two firms given that each firm's output is still dependent upon each other firm's output?