Вычислите:

a) $$2\frac{3}{9} \cdot \frac{3}{8} = \frac{21}{9} \cdot \frac{3}{8} = \frac{7}{3} \cdot \frac{1}{8} = \frac{7}{24}$$

б) $$3\frac{3}{7} \cdot 21 = \frac{24}{7} \cdot 21 = 24 \cdot 3 = 72$$

в) $$3\frac{1}{5} \cdot \frac{15}{24} = \frac{16}{5} \cdot \frac{15}{24} = \frac{2}{1} \cdot \frac{3}{3} = 2$$

Ответ: a) $$\frac{7}{24}$$; б) $$72$$; в) $$2$$