中观微观第5次作业答案史宇鹏提供

1、a) Those points on the budget line which goes through the endowment allocation will simultaneously represent the market baskets owned by two consumers, because each allocation on the budget line is affordable by two consumers and excess demand for each good is zero.b) The contract curve is composed of points where the two consumers indifference curves are tangent to each other. So the two consumers marginal rates of substitution between two goods must be the same at those points.2、a) When the amount of public good is T, then the total surplus of each consumer is:Then the total social surplus is , hence the net social surplus is . So the social optimal hour .b) In the private competitive market, the suppliers only make zero profit. So the market price is 200. Only the third consumer will buy this good, and the quality will be 50.3、a) The quantity of the beehives is determined by the following first order condition:, where MC(Q) andare the marginal cost and marginal revenue faced by the beekeepers respectively. So the beekeeper will maintain 5 hives.b) Social optimal quantity of hives should be derived from the first order condition faced by the “society”: c) There are at least two ways to achieve social efficiency: Let the beekeeper has the right to sale the pollination service to the orchard owner. Or the orchard owner buys the hives and keeps it himself to internalize the externality of bee keeping. 4、a) Yes. Because the waste is produced by the industry and enters into the utility of the residents, but the residents have no right to influence the quantity decision of the waste.b) The total revenue of the industry is given the production Q, so the marginal revenue is 24-2Q. Using MR=MPC condition, we conclude that the equilibrium Q is 22/3, and the equilibrium price is 50/3.c) The social marginal revenue is equal to the private marginal revenue of the industry, but the social marginal cost is the sum of the industrys and the consumers, which is 2+2Q for given Q. So the social optimal quantity of good is 11/2 and so does the waste.d) The industrys marginal cost will change to 2+Q+T, if T is levied for each unit of waste. The optimal production plan will be (22-T)/3. When T equals 11/2, the social optimum will be realized.5、a)B-cardsB-cardsDavidP-cardsP-cardsRon(800,800; 200,4200)b) The endowment allocation is not Pareto efficient, because marginal rates of substitution are not the same. We can see, while . (Both MRSs are in their absolute forms.)c) One form of trade: David trades some