A thin barrier separates two compartments in a rigid insulator box. While the right compartment holds n_He moles of helium at a temperature of T_he, the left compartment holds n_ox moles of oxygen at a temperature of T_ox. The barrier prevents any mixing of the gases. Find the final thermal energy of helium and oxygen in terms of n_ox, n_he and the total initial energy (E_tot) when they reach equilibrium.