For a particular good with price P, market demand is D = IDD P, while market supply is S = P. Calculate the total gains from exchange. What happens to these gains if the government confronts consumers with a sales tax of $2 per unit? How would a price ceiling of $49 {instead of the tax] affect the gains? alternatively, if the government imposes a price floor of $51, what happens to the gains? Now introduce the opportunity to trade internationally at a fixed world price of $43, and determine the total gains from exchange, assuming no intervention by the government. How would these gains be altered by a tax of $1 per unit of imports? If the world price is fixed at $52 {rather than $48}, what happens to the gains when the government implements a tax of $1 per unit of exports