George lives over 15 miles away from the nearest grocery store. Today he bought a gallon of milk along with some other groceries. By the time he got home and put the milk in his refrigerator the milk was already 58°F. George will only drink milk that is 37°F or colder. If the temperature of the milk is modeled by the linear equation y = - 12 13 x + 58, how long will it be before George will drink the milk? (round to nearest whole minute)