On a cold winter day, the outside temperature is –5.0 °C whi…

On a cold winter day, the outside temperature is –5.0 °C while the interior of a well-insulated garage is maintained at 20.0 °C by an electric heater.  Assume the walls have a total area of 75 m2, a thickness of 0.15 m, and a thermal conductivity of 0.042 W/(m · C°).  What is the cost to heat the garage for six hours at these temperatures if the cost of electricity is $ 0.11/kWh?  Note: 1 kWh = 3.6 × 106 J.