Densities and ultrasonic velocities for binary aqueous solutions of poly(ethylene glycol) 6000, disodium succinate, or sodium formate and ternary aqueous solutions of PEG(6000) containing disodium succinate or sodium formate have been measured at T = (298.15, 308.15, and 318.15) K. Using the obtained density and ultrasonic velocity data, we also calculated the adiabatic compressibility values for the aforementioned binary systems and fit them to a polynomial equation. Apparent molal volume data calculated from the density data for binary systems were fit to suitable equations to obtain limiting apparent molal volumes. The data for the density, ultrasonic velocity, and adiabatic compressibility for ternary PEG(6000) + disodium succinate + water and PEG(6000) + sodium formate + water were correlated with a semiempirical equation.