\(Metan:CH_4\\ But-1-en:CH_2=CH-CH_2-CH_3\\ n_{Br_2}=\dfrac{16}{160}=0,1\left(mol\right)\\ C_4H_8+Br_2\rightarrow C_4H_8Br_2\\ n_{C_4H_8}=n_{Br_2}=0,1\left(mol\right)\\ \%m_{C_4H_8}=\dfrac{56.0,1}{7,2}.100\approx77,778\%\\ \Rightarrow\%m_{CH_4}\approx22,222\%\\ n_{CH_4}=\dfrac{7,2-0,1.56}{16}=0,1\left(mol\right)\\ CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\\ C_4H_8+6O_2\rightarrow\left(t^o\right)4CO_2+4H_2O\)