$v_{rms}$ of Helium $ = 4 \times v_{avg}$ of Hydrogen.

$\Rightarrow \large \sqrt \frac{3\times RT}{4}$ $=4 \large \sqrt \frac{R \times 273}{\pi \times 2}$

$\Rightarrow \large\frac{3T}{4} $$ = \large\frac{16\times 8 \times273}{2\pi}$

$\Rightarrow T = 27.18 \times 273 = 7419.1K$