Find the interface temperature between materials A and B if the heat loss is 2500 Btu/h. The area perpendicular to heat flow is 500 ft^2, material A is exposed to gases at 400 F and material B is exposed to air at 75 F. Material A is 6 inches thick and material B is 10 inches thick. Assume k_A = 0.5 Btu/ft hr F and k_B= 0.15 Btu/ft hr F.