Macro quiz..

Problem 1. (Consumer Choice) Lionel watches movies z, while drinking beer, 23. His utility function from consuming the two types of goods is given by U(21. 12) = 5In(21) + 10in(zz) a) Plot Lionel's indifference curve map (graph). Find his MRS analytically (give formula). Find the value of MRS at the consumption bundle (1, 1) and depict it in the graph. b) Using "magic formulas," find the optimal level of consumption of 2, and zy if p; = pa = 5 and m = 45. Plot carefully the optimal point along with the budget line and the indifference curve passing through the optimal point (a graph + two numbers). c) Argue that the commodities are neither gross complements nor gross substitutes (argue using the magic formula, one sentence). For the rest of the problem suppose that Lionel's preferences change and now they are given by (1,12) = d) In a separate graph plot his indifference curves, and find MRS for consumption bundle (2, 1). (a graph tone number). e) Find Lionel's optimal choice given prices p = pa = 5 and m = 45 (two numbers). Is the optimal choice unique? (yeso answer) Problem 2. (Equilibrium with Intertemporal Choice) Consider an intertemporal choice problem with Ambrosia and Fergus. Ambrosia is an athlete with income of 800 when young and 200 when old, Le. = (800, 200). Fergus is a manager who earns 200 when young and 800 when old, Le., his endowment is w= (200, 800). Ambrosia and Fergus have the same utility function given by where i = A, F. a) Plot the Edgeworth box and mark the point corresponding to endowments of Ambrosia and Fergus (graph). b) Give a general economic definition of Pareto efficiency (one sentence). Write the equivalent condition for Pareto efficiency in terms of MRS (equation). Use your equation to verify whether the endowment is Pareto efficient. (argue formally using your condition) c) Find all the allocations that are Pareto efficient (derive formula for the contract curve). Plot the contract curve in the Edgeworth box. d) Find the competitive equilibrium. Calculate borrowing and savings for both agents in your equilibrium. (Hint: use that for the intertemporal choice I t r = " )- Problem 3. (Technology) Suppose a producer has access to the technology given by the Cobb-Douglass production function y = 3xz. a) What can you say about the returns to scale (choos: IRS, CRS or DRS) and MPK (chose: increasing, constant, or decreasing). b) Find the (variable) cost function c(y) given that the prices of inputs are wx = weg = 4.5 (give a function). For the rest of the problem suppose that in order to have access to the technology, the producer first needs to pay fixed cost F = 16 and hence the total cost is given by TC = 16 + c(y). c) Find the supply function of the individual competitive firm and plot it in the graph (give the formula, in the graph mark the prices for which the market will not open). d) Assume that the producers are competitive and there is free entry. Determine the number of firms operating in the industry in the long run if the demand is D(p) = 20-p (one number). Problem 4. (Short Questions) a) A Bernoulli utility function is u(z) = s' and there are two states of the world which are equally likely. Find the certainty equivalent and the expected value of lottery (0,2) (two numbers). Which of the two is bigger (choose one)? Explain why (one sentence). b) Consider an industry in which the market share of the dominant firm is 30%%, while the market share of the five other firms is 10% each. Find HII index for this industry. Is the industry competitive, moderately concentrated, or concentrated? c) Suppose there are two types of managers: talented with productivity 5 and not talented with productivity 3. The types are unobservable to employers and the competitive wage is given by the expected productivity of the manager. Is an MBA diploma from a program that takes three years to complete e = 3 a credible signal if the cost of effort for the not talented agent is c() =e (yeso + one sentence explaining why). Find minimal e for which the MBA diploma is a credible signal. d) Externality: Give two methods through which a government can achieve market efficiency in the presence of a negative externality. (two sentences for each method)Optimization with Inequality Constraints Problem 4. Use the Kuhn-Tucker conditions to find maxima for the following: a. F(x, y) = xy, subject to (1) x" + y