Answer :
rate He = 6 x rate SF₆
Further explanation
Graham's law: the rate of effusion of a gas is inversely proportional to the square root of its molar masses or
the effusion rates of two gases = the square root of the inverse of their molar masses:
[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]
or
[tex]\rm M_1\times r_1^2=M_2\times r_2^2[/tex]
M He = 4 g/mol
M SF₆ = 146 g/mol
[tex]\tt \dfrac{r_{He}}{r_{SF_6}}=\sqrt{\dfrac{146}{4} }=6.04\approx 6\\\\r_{He}=6~r_{SF_6}[/tex]