11. Вычислите: $\frac{8}{15} + (2-\frac{13}{28}) : \frac{25}{49} - 1\frac{1}{4}$

$\frac{8}{15} + (2-\frac{13}{28}) : \frac{25}{49} - 1\frac{1}{4} = $ $\frac{8}{15} + (\frac{56}{28} -\frac{13}{28}) : \frac{25}{49} - \frac{5}{4} = $ $\frac{8}{15} + \frac{43}{28} : \frac{25}{49} - \frac{5}{4} = $ $\frac{8}{15} + \frac{43}{28} \cdot \frac{49}{25} - \frac{5}{4} = $ $\frac{8}{15} + \frac{43}{4} \cdot \frac{7}{25} - \frac{5}{4} = $ $\frac{8}{15} + \frac{301}{100} - \frac{5}{4} = $ $\frac{320}{600} + \frac{1806}{600} - \frac{750}{600} = $ $\frac{320 + 1806 - 750}{600} = \frac{1376}{600} = \frac{344}{150} = \frac{172}{75} = 2\frac{22}{75}$ Ответ: $2\frac{22}{75}$