A closed box is filled with dry ice at a temperature of ?78.4 °C, while the outside temperature is 22.8 °C. The box is cubical, measuring 0.283 m on a side, and the thickness of the walls is 2.10 multiply.gif 10-2 m. In one day, 3.14 multiply.gif 106 J of heat is conducted through the six walls. Find the thermal conductivity of the material from which the box is made.