Выполним действия по порядку:
- $$3\frac{8}{11} = \frac{3*11 + 8}{11} = \frac{41}{11}$$
- $$1\frac{2}{3} = \frac{1*3 + 2}{3} = \frac{5}{3}$$
- $$\frac{41}{11} : \frac{123}{77} = \frac{41}{11} * \frac{77}{123} = \frac{41*77}{11*123} = \frac{41*7*11}{11*41*3} = \frac{7}{3}$$
- $$\frac{7}{3} - \frac{5}{3} = \frac{7-5}{3} = \frac{2}{3}$$
- $$\frac{2}{3} * 2,4 = \frac{2}{3} * \frac{24}{10} = \frac{2*24}{3*10} = \frac{48}{30} = \frac{8}{5}$$
Ответ:
$$\frac{8}{5}$$