Question

two different plates A and B are in composit wall each of dimension 20cm*30cm and their thickness are 3cm and 8cm respectively.thermal conductivity are 0.25 and 0.85 in C.G.S system calculate
1-the thermal resistance of each plate
2-if the free end of plate A at temperature 150c and plate B at temperature 20c calculate the heat current through the combination
3-the temperature of the point of junction
4-the temperature gradient of each plate