(1)==7(2)+(3)(AC-AR). Use the following information to answer the next five questions. AT&T had a monopoly for U.S. phone service during most of the 20 century. The market demand for monthly phone service plans was =80-, where prices are in dollars and quantities in millions. Assume that AT&T had costs of ==40 dollars. 23. If AT&T acts as a monopolist, how many phone plans will they choose to sell. a.10 b.30 c.40(d)20

10 mc: MR =70# 2) ARA CA - # 3 ( AC - AR).0# Use the following information to answer the next five questions. AT&T had a monopoly for U.S. phone service during most of the 20" century. The market demand for monthly phone service plans was P = 80 - Q, where prices are in dollars and quantities in millions. Assume that AT&T had costs of MC = AC = 40 dollars. 23. If AT&T acts as a monopolist, how many phone plans will they choose to sell. a. 10 b. 30 C. 40 d 20 40