A Styrofoam box has a surface area of 0.78 m2 and a wall thickness of 2.0 centimeter. The temperature of the inner surface is 5°C, and the outside temperature is 23°C. If it takes 8.5 hour for 5 kilogram of ice to melt in the container, evaluate the thermal conductivity of the Styrofoam.
__________W/m•K