Help with Chemistry - Equilibrium Concentration?

For the equilibrium PCl5(g) <-> PCl3(g)+Cl2(g), the equilibrium constant Kp has the value 0.497 at 500 K. A gas cylinder at 500 K is charged with PCl5(g) at an initial pressure of 1.66 atm. What are the equilibrium pressures of PCl5 , PCl3 , and Cl2 at this temperature?