If at same temperature and pressure, the densities for two diatomic gases are respectively d1 and d2, then the ratio of velocities of sound in these will be
$\sqrt{\dfrac{\text{d}_2}{\text{d}_1}}$
$\sqrt{\dfrac{\text{d}_1}{\text{d}_2}}$
d1d2
$\sqrt{\text{d}_1\text{d}_2}$