3. Opportunity Cost Dina and Juanita are roommates. They spend most of their time studying (of course), but they leave some time for their favorite activities: making pizza and brewing root beer. Dina takes 3 hours to brew a gallon of root beer and 2 hours to make a pizza. Juanita takes 7 hours to brew a gallon of root beer and 5 hours to make a pizza. Dina's opportunity cost of brewing a gallon of root beer is2/3 pizza.