A night-club owner has both graduate student and professor customers. The demand for drinks by a typical graduate student is Q_S=18-2P. The demand for drinks by a typical professor is Q_A=12-P. There are equal numbers of each. The marginal cost of each drink is $2. Assume no fixed costs.

If the club owner can separate the groups and practice third-degree price discrimination, what will be the price be set at for professors?

5

7

3

9