Jacob moved into a new house with 4 friends, and they want to throw a party with a DJ called Lil Huddy. All of them love the DJ, but they can't agree how long his set should be.

Jacob's demands for minutes of music is given by P =92 - 3.5Q, and his friends having identical demand curves as him. Lil Huddy charges $15/minute.

The friends can't come to an agreement on how long to book Lil Huddy, forcing them to choose individually, how many fewer minutes will they buy compares to the social optimum.