Hướng dẫn giải:  ${{C}_{2}}{{H}_{6}}O\text{ }+\text{ }\frac{7}{2}{{O}_{2}}\to 2C{{O}_{2}}+\text{ }3{{H}_{2}}O$

        x                           2x         3x   (mol)

${{C}_{3}}{{H}_{8}}O\text{ }+\text{ }\frac{9}{2}{{O}_{2}}\to 3C{{O}_{2}}+\text{ }4{{H}_{2}}O$

    x                           3x         4y      (mol)

Ta có hệ phương trình  $\left\{ \begin{align}& x+3y=0,08 \\& 3x+4y=0,11 \\\end{align} \right.$ $\to \left\{ \begin{align}& x=0,01 \\& y=0,02 \\\end{align} \right.$  (mol)

m_C2H5OH = 0,01 . 46 = 0,46 (g)

m_C3H7OH = 0,02 . 60 = 1,2 (g)

m_{hỗn hợp} = 0,46 + 1,2 = 1,66 (g)

% ${{m}_{{{C}_{2}}{{H}_{5}}OH}}$ = 0,46 : 1,66 . 100 = 27,71 (%) $\to $  %${{m}_{{{C}_{3}}{{H}_{7}}OH}}$= 72,29 (%)