Cowflop, WI has 1,000 people. Every year they have a fireworks show on the Fourth of July. The citizens are interested in only two things, drinking milk and watching fireworks. Fireworks cost 1 gallon of milk per unit. People in Cowflop have identical utility functions Ui(xi, g)=xi+g1/2/20, where xi is the number of gallons of milk per year consumed by citizen i, and g is the number of units of fireworks exploded in the town’s Fourth of July extravaganza. (Private use of fireworks is outlawed.)

a.Solve for the absolute value of each citizen’s marginal rate of substitution between fireworks and milk.
b. Find the Pareto optimal amount of fireworks for Cowflop.


a我还会。。。但是b我知道结果，是625.。但是实在想不出来怎么得出来的。。。。求详解。。。万分感谢。