An airport is located next to a housing development. Where X is the number of planes that land per day and Y is the number of houses in the housing development, profits of the airport are 22X-X 2 and pro ts of the developer are 26Y-Y 2 -XY . Let H1 be the number of houses built if a single pro t-maximizing company owns the airport and the housing development. Let H2 be the number of houses built if the airport and the housing development are operated independently and the airport has to pay the developer the total 'damages' XY done by the planes to developer's profits. Then