We have performed molecular dynamics simulations to obtain internal energy and pressure of helium-neon and helium-krypton mixtures at different densities using accurate recently two-body ab initio potentials supplemented by quantum corrections following the Feynman-Hibbs approach. The significance of this work is that the three-body expression of Wang and Sadus [22] was used to improve prediction of the pressures and internal energies of helium + krypton and helium + neon mixtures without requiring an expensive three-body calculation. Our results show a good agreement with the corresponding experimental data. (C) 2009 Elsevier B.V. All rights reserved.