Two uninsulated, rigid tanks contain air. Initially, tank A hold 1 lbm of air at 1440 degrees R, and tank B has 2 lbm of air at 900 degrees R. The initial pressure in each tank is 50 psi. A valve in the line connecting the two tanks is opened and the contents are allowed to mix. Eventually, the contents of the tanks come to equilibrium at the temperature of the surrounding, 520 degrees R. Determine the amount of energy transfer by heat, in Btu, and the final pressure, in pis.