a. Assume there are two goods, cigarette (X) and fruit drink (Y). Derive the expression for excess burden of a selective excise tax on: i. ii. Good X in terms of ex, Px, X and tx Good Y in terms of ey, Py, Y and ty [Hint: e, is the price elasticity of demand for good i, P, is price of good i, ti is the rate of taxon good i, where i is quantity of good X and Y, respectively] b. Assuming that there are no cross-effects between cigarette (X) and fruit drink (Y), state and derive the Ramsey Rule