2. A thermometer reading 18"F is brought into a room, the temperature of which is 70"F. One minute later, the thermometer reading is 31"F. Find the temperature reading 5 minutes after it was brought into the room. At what time will the temperature reading be 67.8 F? Hint: cooling: = -k(T - Tm); heating: - = k(Tm - 7); temp at time t: T = Tm + (To -T, )e-kt