11. Four roommates live together in an apartment. The apartment could use a new toilet which would cost $1000 (including installation). The table below shows the marginal benefit of having a new toilet for each roommate (roommates 1 and 3 really want it, whereas roommates 2 and 4 are gross and don't mind the old toilet that much). Assume the toilet is non-excludable and non-rival (quite a stretch). Then