\[7\frac{11}{12}\ :3\frac{1}{6} = \frac{95}{12}\ :\frac{19}{6} = \frac{95 \cdot 6}{12 \cdot 19} =\]
\[= \frac{19 \cdot 5 \cdot 6}{6 \cdot 2 \cdot 19} = \frac{5}{2} = 2\frac{1}{2}\]