A volume of 0.3 m3 of O2 at 200 K and 8 MPa is mixed with 0.5

Question:

A volume of 0.3 m3 of O2 at 200 K and 8 MPa is mixed with 0.5 m3 of N2 at the same temperature and pressure, forming a mixture at 200 K and 8 MPa. Determine the volume of the mixture, using
(a) The ideal-gas equation of state,
(b) Kay’s rule, and
(c) The compressibility chart and Amagat’s law.