1.
It is known that the temperature in a room is +20C+20\,^\circ\text{C} when the outdoor temperature is 20C-20\,^\circ\text{C}, and the room is at +10C+10\,^\circ\text{C} when the outdoor temperature is 40C-40\,^\circ\text{C}. Determine the temperature of the radiator heating the room.