Final answer:
The market demand function when there are two identical buyers with individual demand functions of P = 40 - Q is P = 40 - (Q/2), with Q representing the combined quantity demanded by both buyers.
Step-by-step explanation:
The student's question involves finding the market demand function when there are two identical buyers in the market, and each buyer's demand function is given by P = 40 - Q. When we have two identical buyers, the market demand is simply the sum of the individual demands of both buyers. If one buyer's demand function is P = 40 - Q, and considering there are two such buyers, the total quantity demanded at each price level is double. Therefore, the market demand function becomes P = 40 - (Q/2), assuming that Q represents the total quantity demanded in the market. To find the combined market demand function, we add the individual quantities demanded for any given price. As a result, the market demand function is P = 40 - (Q1 + Q2), where Q1 and Q2 are the quantities demanded by buyer one and two, respectively.