488. 3) $$2\frac{1}{2} \cdot 48 - 3\frac{2}{3}:\frac{1}{18}+5\frac{5}{12}:\frac{7}{36}$$

$$2\frac{1}{2} \cdot 48 - 3\frac{2}{3}:\frac{1}{18}+5\frac{5}{12}:\frac{7}{36} = \frac{5}{2} \cdot \frac{48}{1} - \frac{11}{3}:\frac{1}{18} + \frac{65}{12}:\frac{7}{36} = $$

$$ = \frac{5 \cdot 48}{2 \cdot 1} - \frac{11 \cdot 18}{3 \cdot 1} + \frac{65 \cdot 36}{12 \cdot 7} = \frac{240}{2} - \frac{198}{3} + \frac{2340}{84} = $$

$$ = 120 - 66 + \frac{195}{7} = 54 + \frac{195}{7} = \frac{54 \cdot 7 + 195}{7} = \frac{378 + 195}{7} = \frac{573}{7} = 81\frac{6}{7}$$

Ответ: $$81\frac{6}{7}$$