$$\frac{11}{12} - x = \frac{11}{24}$$
$$x = \frac{11}{12} - \frac{11}{24}$$
$$x = \frac{11 \cdot 2 - 11}{24} = \frac{22 - 11}{24} = \frac{11}{24}$$
Ответ: $$x = \frac{11}{24}$$