A partitioned volume initially contains two gases separated by a partition. The partition is removed suddenly?

A partitioned volume initially contains Helium and Argon separated by a partition. ume each can be treated as an ideal monatomic gas. The partition is removed suddenly and the two gases subsequently mix to form a geneous mixture. No energy is exchanged with the surroundings and the energy of the total system remains constant. Calculate the temperature and pressure of the equilibrium mixture.