Two residents develop their communal area into a community garden. The marginal benefit of each resident i = 1, 2 from the garden is given by MB1 = 100 Q and MB2 = 60 Q, where Q is the size of the garden in m2 . The cost of developing the communal area into a garden is C(Q) = 50Q. Assume that the community garden is non-rivalry and non-excludable