Найдем значение выражения:
$$ (3 - \frac{15}{28} \cdot \frac{1}{6}) \cdot \frac{2}{19} = (3 - \frac{15 \cdot 1}{28 \cdot 6}) \cdot \frac{2}{19} = (3 - \frac{15}{168}) \cdot \frac{2}{19} = (3 - \frac{5}{56}) \cdot \frac{2}{19} = (\frac{3 \cdot 56}{56} - \frac{5}{56}) \cdot \frac{2}{19} = (\frac{168 - 5}{56}) \cdot \frac{2}{19} = \frac{163}{56} \cdot \frac{2}{19} = \frac{163 \cdot 2}{56 \cdot 19} = \frac{163}{28 \cdot 19} = \frac{163}{532} $$
Ответ: $$ \frac{163}{532} $$