Consider two boxes containing ideal gases A and B such that their temperatures, pressures and number densities are same. The molecular size of A is…

Consider two boxes containing ideal gases $\displaystyle A$ and $\displaystyle B$ such that their temperatures, pressures and number densities are same. The molecular size of $\displaystyle A$ is half of that of $\displaystyle B$ and mass of molecule $\displaystyle A$ is four times that of $\displaystyle B$. If the collision frequency in gas $\displaystyle B$ is $\displaystyle 32 \times 10^{18} / \mathrm{s}$ then collision frequency in gas $\displaystyle A$ is $\displaystyle \_\_\_\_$/s.