11. Assign 9 students to 3 dormitories, Jia, Yi, and Bing, with each dormitory requiring 4 people (beds are not distinguished), there are $\qquad$ different ways to do this.
11.11130
$$
\left(\frac{C_{9}^{1} C_{8}^{4}}{P_{2}^{2}}+C_{9}^{2} C_{7}^{3}+\frac{C_{9}^{3} C_{6}^{3}}{P_{3}^{3}}\right) \cdot P_{3}^{3} .
$$