问答题 Suppose Q_D=100-2P, and Q_S=-50+3P.
(a)What is the original market equilibrium price and quantity?
(b)The government imposes a tax of ＄1 per unit. Compute the after-tax equilibrium. What are the new equilibrium price and quantity? How much revenue does the government collect?

【正确答案】

【答案解析】(a)Setting Q_D=Q_S, the original equilibrium is the solution to 100-2P=-50+3P or P* =＄30 and Q*=40.
(b)After a ＄1 tax is imposed, we can solve for the price received by sellers: 100-2(P_S+1)= -50+ 3P_Sor P_S* = 148/5 =＄29.60. The new quantity is Q*=38.8. The government collects ＄×38.8=＄38.80.