A mixture of 2 moles of helium gas (atomic mass 4u) and 1 mole of argon (atomic mas s 40u) is kept at 300 K in a container. The ratio of their root mean square speed is $\left[\frac{{\mathrm{u}}_{\mathrm{rmsHe}}}{{\mathrm{u}}_{\mathrm{rmsAr}}}\right]$ close to;