Two slabs of the same area A ={A} cm², and the thickness L₁=7cm and L₂=24cm and thermal conductivities k₁=8W/m ^oC and k₂=20W/m ^oC are in thermal contact with each other as shown. The temperatures of their outer surfaces are T_c = -17^oC and T_h=22.5^oC respectively. Determine the temperature at the interface. State your answer in ^oC to the nearest 0.1^oC.

Take 0^oC=273K