$*)\begin{cases}CH_4:x mol \\ C_2H_4:y mol\\C_2H_2:z mol\\16x+28y+26z=8,6 gam\\n_{Br_2}=\frac{48}{160}=0,3 mol\\y+2z=n_{Br_2} \end{cases}$$*)\begin{cases}CH_4:tx mol \\ C_2H_4:ty mol\\C_2H_2:tz mol\\t(x+y+z)=\frac{13,44}{22,4} mol\\m_{C_2Ag_2}=(240tz)=36 gam \end{cases}$
$\Rightarrow \begin{cases}16x+28y+26z=8,6 gam \\ y+2z=0,3 mol\\t(x+y+z)=0,6 mol\\tz=0,15 mol \end{cases}\Rightarrow \begin{cases}x=0,2 mol \\ y=0,1 mol\\z=0,1 mol \end{cases}\Rightarrow \%CH_4=50\%$
$\Rightarrow Chon:C$