Thelma and Louise are neighbors. During the winter, it is impossible for a snowplow to clear the street in front of Thelmas house without clearing the front of Louises. Thelmas marginal benefit from snowplowing services is 12-Z, where Z is the number of times the street is plowed. Louises marginal benefit is 8-2Z. The marginal cost of getting the street plowed is $16.

Sketch the two marginal benefit schedules and the aggregate marginal benefit schedule. Draw in the marginal cost schedule, and find the efficient level of provision for snowplowing services. If Thelma and Louise can come to an agreement that allows for the efficient level of provision of the snowplowing services, what are three possible ways in which they can share the costs? If Thelma and Louise cannot come to an agreement, how many times will the street be plowed?