My daughter shares an apartment with six other women. Four share her appreciation for the music of Ella Marija Lani Yelich-O'Connor, a.k.a. Lorde. My daughter and the other Lorde fans would happily pay $5 each to listen to her music on returning home from work. The other two women are completely tired of the show and of the melodrama, and would pay $10 each to not have to hear her. 1. What is the efficient outcome? Would you expect this to happen? 2. Does it matter who owns the stereo? What if one of the women who doesn't like Lorde owns the stereo? Would that change the efficient outcome? 3. What if 2 of the Lorde fans move out? Would it matter if my daughter owned the stereo?