\(\begin{array}{l} {C_2}{H_4} + B{r_2} \to {C_2}{H_4}B{r_2}\\ {C_2}{H_2} + 2B{r_2} \to {C_2}{H_2}B{r_4}\\ hh:C{H_4}(a\,mol),{C_2}{H_4}(b\,mol),{C_2}{H_2}(c\,mol)\\ 16a + 28b + 26c = 9,9\\ b + 2c = \dfrac{{64}}{{160}}\\ 28b + 26c = 6,7\\  =  > a = 0,2;b = 0,1;c = 0,15\\ mC{H_4} = 0,2 \times 16 = 3,2g\\ m{C_2}{H_4} = 0,1 \times 28 = 2,8g\\ m{C_2}{H_2} = 0,15 \times 26 = 3,9g \end{array}\)