A large iron slab $($ $=7870$ kg$/$m$3,$ cp $=447$ J$/$kg$$K$,$ and k $=80\mathrm{.}2$ W$/$m$$K$)$ was initially heated to a uniform temperature of $150$C and then placed on concrete floor $($ $=1600$ kg$/$m$3,$ cp $=840$ J$/$kg$$K$,$ and k $=0\mathrm{.}79$ W$/$m$$K$).$ The concrete floor was initially at a uniform temperature of $30$C$.$

Determine the surface temperature between the iron slab and concrete floor.$($You must provide an answer before moving to the next part.$)$

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The surface temperature between the iron slab and concrete floor is $$C