A valve connects two tanks containing carbon monoxide. One tank contains 2 kg of CO at 77 °C and 0.7 bar; the other holds 8 kg of CO at 27 °C and 1.2 bar. The valve is opened and the gases mix while receiving heat from the surroundings; the final equilibrium temperature is 42 °C. Using the ideal-gas model, determine the final pressure in bar.