This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Answers to Selected Questions in Practice Problem Set 1 ECON 11 Summer Session C 2010 Microeconomic Theory Yong Yang 1. [Market equilibrium] (a) omitted. (b) Q D = Q S = 240 is the equilibrium quantity at the equilibrium price P = 90. The demand elasticity is ε D =- 3 2 , and the supply elasticity is ε S = 9 8 at the equilibrium. (c) The consumer surplus is 7,200, and the producer surplus is 9,600. The social total surplus is 16,800. (figure omitted) (d) The new equilibrium is P = 150 and Q D = Q S = 420. (e) CS increases to 44,100, and PS also increases to 29,400. The social total surplus increases to 73,500 consequently. 2. [Sales tax] (a) The equilibrium is P = 260 and Q D = Q S = 450. (b) CS is 50,625, PS is 33,750, and thus STS is 84,375. (c) When the sales tax is imposed, sellers get the market price, so P S = P , but buyers pay more than the market price, so P D = P + 25. Writing the quantities demanded and supplied in terms of the market price P , Q D =970- 2 P D = 970- 2( P + 25) = 920- 2 P Q S =- 330 + 3 P S =- 330 + 3 P At the equilibrium, Q D = Q S , so we have 920- 2 P =- 330 + 3 P and thus P = 250 at the equilibrium. From this, we get P D = 275 and P S = 250. The equilibrium quantity would be Q D = Q S = 420. The new equilibrium (market) price is lower than before the sales tax is imposed. (However, consumers pay more than the original equilibrium price $260.) The new equilibrium quantity is less than before. (d) Consumers have the demand curve Q D = 970- 2 P D , and buy 420 units by paying P D = 275 at the equilibrium. Note that the intercept of the demand curve is 485. So the consumer surplus would be CS = 1 2 × (485- 275) × 420 = 44 , 100 Sellers have the supply curve Q S =- 330 + 3 P S , and sell 420 units to get P S = 250 per unit at the equilibrium. Note that the intercept of the supply curve is 110. So the producer surplus is PS = 1 2 × (250- 110) × 420 = 29 , 400 There is a government revenue from the sales tax, which amounts to 25 × 420 = 10 , 500. So the social total surplus is 44 , 100 + 29 , 400 + 10 , 500 = 84 , 000. This is less than the one in (b), so there is a deadweight loss of $375....
View Full Document
This note was uploaded on 10/04/2011 for the course ECON 11 taught by Professor Cunningham during the Summer '08 term at UCLA.
- Summer '08
- Market Equilibrium