The coefficient of linear expansion of steel is 12x 10^-6/C degrees. A railroad track is made of individual rails of steel 1.0 km in length.

 The coefficient of linear expansion of steel is 12x 10^-6/C degrees. A railroad track is made of individual rails of steel 1.0 km in length. By what length would these rails change between a cold day when the temperature is -10 degrees C and a hot day a 30 degrees C?