The consistency in units is often the case
Since the problem doesn't give Delta G naught, we calculate Delta G reaction assuming the reaction is at equilibrium (ΔG = 0)
ΔG° reaction (kJ) = - R (J/°K.mol) x T(°K) x ln (Pp/Pr)
In this case, convert R = 8.314x10-3 (kJ/°K.mol)