2) $$2\frac{7}{16}y + 3\frac{5}{20}y + 1\frac{3}{8}y = 2\frac{7}{16}y + 3\frac{1}{4}y + 1\frac{3}{8}y = 2\frac{7}{16}y + 3\frac{1 \cdot 4}{4 \cdot 4}y + 1\frac{3 \cdot 2}{8 \cdot 2}y = 2\frac{7}{16}y + 3\frac{4}{16}y + 1\frac{6}{16}y = (2+3+1)y + (\frac{7}{16} + \frac{4}{16} + \frac{6}{16})y = 6y + \frac{17}{16}y = 6y + 1\frac{1}{16}y = 7\frac{1}{16}y$$
Ответ: $$7\frac{1}{16}y$$