] Consider the following simplified model of airline yield management; your flight has a that has 50 unfilled coach seats and is due to depart in 10 days. There are two fares on the flight: full fare and discount. The price of the discount fare is $250; whereas the price of full fare is determined after we reserve the discounted seats on the plane. For example, if the number of seats available on the plane is i, and we decide to sell s many of them at discount price then the price of full fare is defined as