The New York Times reported (Feb. 17, 1996) that subway ridership declined after a fare increase: "There were nearly four million fewer riders in December 1995, the first full month after the price of a token increased [20 percent], than in the previous December, a 4.3 percent decline." (a) Use these data to find the point price elasticity of demand for subway rides before the price increase. (b) According to your estimate, what happens to the Transit Authority's revenue when the fare rises?