Saturated liquid propane (C3H8), is throttled adiabatically down to a pressure of P2=1.5 bar. Calculate the pressure P1 at the inlet of the throttling valve, if the vapor fraction of propane after the throttling is 0.65 . Assume that the thermal properties of propane are described by the Peng-Robinson Equation of State. Express your answer in bar and round your numerical result to one decimal digit