If Castor's demand curve is described by q = 40

Question

If Castor's demand curve is described by q = 40 - p and Pollux's demand curve is given by q = 60 - 2p, then each of their demand curves will pass through the point q = 20, p = 20.Therefore if they are the only two consumers in a market, the market demand curve will also pass through q = 20, p = 20.

Quizplus · Accepted Answer

The fact that Castor and Pollux's demand curves pass through q=20 and p=20 does not necessarily imply that the market demand curve will also pass through these values. The market demand curve is the horizontal sum of individual demand curves, and the exact shape of this curve will depend on the number of consumers in the market and their individual demand functions.