б) 6 2/5 * (3 2/5 - 11/15)

б) \(6 \frac{2}{5} \cdot (3 \frac{2}{5} - \frac{11}{15}) = \frac{32}{5} \cdot (\frac{17}{5} - \frac{11}{15}) = \frac{32}{5} \cdot (\frac{51 - 11}{15}) = \frac{32}{5} \cdot \frac{40}{15} = \frac{32}{5} \cdot \frac{8}{3} = \frac{256}{15} = 17 \frac{1}{15}\)