Heat Transfer - The rate of heat transfer through the wall

Consider a 5-m-high, 8-m-long, and 0.22-m-thick wall whose representative cross section is as given in the following figure. The thermal conductivities of various materials used, in W/m·K, are kA = kF =2, kB =8, kC =20, kD =15, and kE =35. The left and right surfaces of the wall are maintained at uniform temperature of 300°C and 100°C, respectively. Assuming heat transfer through the wall to be one-dimensional, determine (a) the rate of heat transfer