c
\(1\) મોલ વાયુ \( \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1\) મોલ વાયુ 

\(\,\,\,\,\,\,\,\,\,{\gamma _{\text{1}}} = \frac{7}{5}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\gamma _{\text{2}}} = \frac{4}{3}\)

\({\gamma _{mix}} = \frac{{{{({C_P})}_{mix}}}}{{{{({C_u})}_{mix}}}} \Rightarrow \,\frac{{{n_1} + {n_2}}}{{{\gamma _{mix}} - 1}} = \frac{{{n_1}}}{{{\gamma _1} - 1}} + \frac{{{n_2}}}{{{\gamma _2} - 1}}\)

\(\frac{{1 + 1}}{{{\gamma _{mix}} - 1}} = \frac{1}{{\frac{7}{5} - 1}} + \frac{1}{{\frac{4}{5} - 1}} \Rightarrow {\gamma _{mix}} = \frac{{15}}{{11}}\)