Some versions:-
Suppose there are three consumer types A, B, C equal in number. A certain firm sells two products 1 and 2 and has zero marginal cost. The willingness-to-pay values are wA = (6, 2), wB = (4, 3), wC = (9, 3), and consumers purchase at most one version. What prices should the firm set for the two versions? What are the resulting CS, π, and SS?