1) $$ 1 \frac{1}{15} - \frac{6}{12} - \frac{5}{8} + \frac{3}{15} = (1 \frac{1}{15} + \frac{3}{15}) - (\frac{6}{12} + \frac{5}{8}) = 1 \frac{4}{15} - (\frac{1}{2} + \frac{5}{8}) = 1 \frac{4}{15} - (\frac{4}{8} + \frac{5}{8}) = 1 \frac{4}{15} - \frac{9}{8} = \frac{19}{15} - \frac{9}{8} = \frac{19 \cdot 8}{15 \cdot 8} - \frac{9 \cdot 15}{8 \cdot 15} = \frac{152}{120} - \frac{135}{120} = \frac{152 - 135}{120} = \frac{17}{120} $$
2) $$(\frac{11}{24} + \frac{3}{16}) \cdot 48 = (\frac{11 \cdot 2}{24 \cdot 2} + \frac{3 \cdot 3}{16 \cdot 3}) \cdot 48 = (\frac{22}{48} + \frac{9}{48}) \cdot 48 = \frac{31}{48} \cdot 48 = 31$$
Ответ: 1) $$\frac{17}{120}$$; 2) 31