Answer:
We know that the equation for molecules is:
$ c=\sqrt{\frac{3RT}{M}} $
Where, M represents the molar mass of the gas
$ v=\sqrt{\frac{\gamma P}{\rho }}=\sqrt{\frac{\gamma RT}{M}} $
We know that, $ PV=nRT $
$ n=1 $
$ \gamma =\frac{{{C}_{p}}}{{{C}_{v}}} $
$ \frac{c}{v}=\frac{\sqrt{\frac{3RT}{M}}}{\sqrt{\frac{\gamma RT}{M}}} $
$ \frac{c}{v}=\sqrt{\frac{3}{7/5}}=\sqrt{\frac{15}{7}} $
which is a constant.