40. \(\frac{6}{7}\) : \(\frac{11}{18} - \frac{5}{12}\)

1. Calculate parenthesis: $$\frac{11}{18} - \frac{5}{12} = \frac{22}{36} - \frac{15}{36} = \frac{7}{36}$$.
2. Divide: $$\frac{6}{7} : \frac{7}{36} = \frac{6}{7} \cdot \frac{36}{7} = \frac{216}{49}$$.
3. Convert to mixed number: $$\frac{216}{49} = 4 \frac{20}{49}$$.