Draw the PPF's for Pat and Kris, assume the relevant time period is a 12 hour day. Show the intercepts and slopes for Pat and Kris.
Pat and Kris are roommates. They spend most of their time studying (of course), but some time for their favorite activities: making pizza and brewing root beer. Pat takes 4 hours to brew a gallon of root beer and 2 hours to make a pizza. Kris takes 6 hours to brew a gallon of root beer and 4 hours to make a pizza.