Ответ:

А) \(0.3 \cdot 300000 \cdot 0.03 = 90000 \cdot 0.03 = 2700\).

Б) \(6\frac{3}{14} : \left(1\frac{5}{6}+2\frac{1}{14}\right)\).

Преобразуем смешанные числа: \(6\frac{3}{14}=\frac{87}{14}\), \(1\frac{5}{6}=\frac{11}{6}\), \(2\frac{1}{14}=\frac{29}{14}\).

\(\frac{11}{6}+\frac{29}{14}=\frac{77}{42}+\frac{87}{42}=\frac{164}{42}=\frac{82}{21}\).

\(\frac{87}{14}:\frac{82}{21}=\frac{87}{14}\cdot\frac{21}{82}=\frac{261}{164}=1\frac{97}{164}\).

В) \(\left(5\frac{1}{24}-4\frac{1}{30}\right)\cdot60=\left(\frac{121}{24}-\frac{121}{30}\right)\cdot60\).

\(\left(\frac{121}{24}-\frac{121}{30}\right)\cdot60=\frac{121}{120}\cdot60=\frac{121}{2}=60.5\).

Ответ: А) 2700; Б) \(1\frac{97}{164}\); В) 60,5.