6. Consider a monopolist that practices third-degree price discrimination, i.e., can charge different prices to different groups of consumers. A fact about each group's marginal revenue is that it can be expressed in terms of price (to the group) and (group) demand elasticity. Specically, for group i, we can write: 1 MRi : Pi[1+]. E. (i) (8 pts.) Assuming two groups and differing demand elasticities at the prot maximum, how can the latter fact be used to deduce how prices differ between the two groups? Explain. (ii) (8 pts.) Suppose that at the optimum both groups have the same demand elasticity. What does this say about the profitability of third-degree price discrimination (i.e., relative to the monopolist that cannot price discriminate)? Explain of course