help me out and pleas check u works

A 3.00-L vessel contained 9.10×10^-2 mol of gaseous PCl₃, 9.48×10^-2 mol of gaseous PCl₅, and 8.80×10^-2 mol of Cl₂ gas at equilibrium at 242°C. 
Calculate the value of K_eq (expressed in terms of the molar concentrations) for the reaction

PCl₃(g) + Cl₂(g)  PCl₅(g)