\[2\frac{2}{5}\ :1\frac{1}{15} = \frac{12}{5}\ :\frac{16}{15} = \frac{12}{5} \cdot \frac{15}{16} =\]
\[= \frac{3 \cdot 4 \cdot 5 \cdot 3}{5 \cdot 4 \cdot 4} = \frac{9}{4} = 2\frac{1}{4}\]