1 - Assume the firm sets the per-unit price equal to marginal cost. Calculate the profit-maximizing entry fee that serves both customer groups.

The individual inverse demand for customers in group one equals: P1 = 20 - q1. The individual inverse demand for customers in group 2 equals: P2 = 20 - 2q2. The marginal cost of production is constant and equal to $2/unit. Assume an equal number of customers in each group.