3. \(\dfrac{3\cdot\left(0,5:1,25+\frac{7}{5}:1\frac{4}{7}-\frac{3}{11}\right)}{\left(1,5+\frac{1}{4}\right):18\frac{1}{3}}\)

Вычислим выражение в числителе:

\[0,5:1,25=\frac{1}{2}:\frac{5}{4}=\frac{2}{5}.\]

\[\frac{7}{5}:1\frac{4}{7}=\frac{7}{5}:\frac{11}{7}=\frac{49}{55},\qquad \frac{3}{11}=\frac{15}{55}.\]

\[\frac{2}{5}+\frac{49}{55}-\frac{15}{55}=\frac{22+49-15}{55}=\frac{56}{55}.\]

Числитель: \(3\cdot\frac{56}{55}=\frac{168}{55}\).

Знаменатель:

\[\left(1,5+\frac14\right):18\frac13=\frac74:\frac{55}{3}=\frac{21}{220}.\]

\[\frac{168}{55}:\frac{21}{220}=\frac{168}{55}\cdot\frac{220}{21}=32.\]

Ответ: 32.