Heat And Thermodynamics

Two plates \(\mathrm{A}\) and \(\mathrm{B}\) have thermal conductivities \(84 ~\mathrm{Wm}^{-1} \mathrm{~K}^{-1}\) and \(126 ~\mathrm{Wm}^{-1} \mathrm{~K}^{-1}\) respectively. They have same surface area and same thickness. They are placed in contact along their surfaces. If the temperatures of the outer surfaces of \(\mathrm{A}\) and \(\mathrm{B}\) are kept at \(100^{\circ} \mathrm{C}\) and \(0{ }^{\circ} \mathrm{C}\) respectively, then the temperature of the surface of contact in steady state is _____________ \({ }^{\circ} \mathrm{C}\).