Выполним вычисление по действиям:
$$8.62 - 8.37 + 1\frac{23}{60} + \frac{1}{5} = 0.25 + 1\frac{23}{60} + \frac{1}{5} = 0.25 + 1\frac{23}{60} + \frac{12}{60} = 0.25 + 1\frac{35}{60} = 0.25 + 1\frac{7}{12} = \frac{1}{4} + \frac{19}{12} = \frac{3}{12} + \frac{19}{12} = \frac{22}{12} = \frac{11}{6}$$
$$3.5 - 2\frac{3}{4} = 3.5 - 2.75 = 0.75 = \frac{3}{4}$$
$$\frac{3}{4} : \frac{1}{5} = \frac{3}{4} \cdot 5 = \frac{15}{4}$$
$$\frac{15}{4} - 2.5 = \frac{15}{4} - \frac{10}{4} = \frac{5}{4}$$
$$\frac{\frac{11}{6}}{\frac{5}{4}} = \frac{11}{6} \cdot \frac{4}{5} = \frac{11 \cdot 2}{3 \cdot 5} = \frac{22}{15}$$
$$\frac{22}{15} \cdot \frac{3}{11} = \frac{2 \cdot 1}{5 \cdot 1} = \frac{2}{5} = 0.4$$
Ответ: 0.4