A mixture of 2 moles of helium gas (atomic mass = 4 amu) and 1 mole of argon gas (atomic mass = 40 amu) is kept at 300 K in a container. The ratio of the r.m.s. speeds  $\left(\frac{{\mathrm{v}}_{\mathrm{rms}}\left(\mathrm{helium}\right)}{{\mathrm{v}}_{\mathrm{rms}}\left(\mathrm{argon}\right)}\right)$  is