A hiker with a skin surface area of 1.3 m² is protected from hypothermia (the cold) by a close-fitting sleeping bag 30 mm thick. If her skin temperature is 34°C and she can safely lose 85 W of heat by conduction through the sleeping bag, what is the lowest outside temperature for which the sleeping bag provides adequate protection? Ignore heat losses due to convection or radiation. Coefficient of thermal conductivity of the sleeping bag = 0.019 Wm¹¹°C-¹
