A composite plane wall consists of a 9 in thick layer of brick and a 4 in thick layer of insulation. The outer surface temperatures of the brick and insulation are 1260 degreeR and 560 degreeR, respectively , and there is perfect contact at the interface between the two layers. Determine at steady state the instantaneous rate of heat transfer, in Btu/h per ft^2 of surface area, and the temperature in degreeR, at the interface between the brick and the insulation.