Eric, Kenji, and Paolo are roommates who are trying to decide how much money each should contribute to a party they are throwing. • Paolo does not care about the party and is on a tight budget. Therefore, he prefers to contribute no money to the party, and his utility declines at a constant rate as the roommates increase the amount of money they spend. • Kenji would ideally contribute $15 because he only wants to buy pizza. However, he would prefer contributing $55 to contributing $0 and not having a party at all. • Eric wants to buy a $120 keg of beer and $45 worth of pizza. Therefore, he would ideally like each to contribute $55 to the party, but if the others are unwilling to contribute that much, he would settle for buying just the pizza (and contributing $15 each) and asking guests to bring beer.