A excess free energy mixing rule with Peng-Robinson EOS modified by Stryjek and Vera has been proposed in order to predict high-pressure VLE using low ASOG parameters. The mixing rule uses a zero-pressure excess free energy and the condition of quardratic composition dependence of second virial coefficient. Prediction is made for binary and ternary systems containing methanol, ethanol, water, and acetone at low and high pressures. With low-pressure ASOG parameters, high-pressure VLE have been predicted.