A steady state one dimensional heat transfer is taking place through a composite wall which consists of three materials A, B, C (are in series). The temperature, thermal conductivity and the thickness of the inner wall or inner surface is 130 degree celsius, 20 W/m 0C and 0.1 m. The thermal conductivity of B is 25 W/m 0C and the thickness is 0.2 m. For C the thermal conductivity is 100 W/m degC and the outer temperature is 30 degC and thickness is 0.3 m. Calculate the value of heat transfer rate and the temperature at the interfaces.