4. Вычислите: \(\dfrac{24}{0{,}8:1{,}2}+\left(\dfrac{15}{16}-\dfrac{19}{12}\right):\dfrac{5}{24}\).

Выполним действия по порядку:

1. \(0{,}8:1{,}2=\dfrac{8}{10}:\dfrac{12}{10}=\dfrac{2}{3}\).
2. \(24:\dfrac{2}{3}=24\cdot\dfrac{3}{2}=36\).
3. \(\dfrac{15}{16}-\dfrac{19}{12}=\dfrac{45}{48}-\dfrac{76}{48}=-\dfrac{31}{48}\).
4. \(-\dfrac{31}{48}:\dfrac{5}{24}=-\dfrac{31}{48}\cdot\dfrac{24}{5}=-\dfrac{31}{10}\).
5. \(36-\dfrac{31}{10}=\dfrac{360-31}{10}=\dfrac{329}{10}=32{,}9\).

Ответ: 32,9.