11. (3 points) As shown in the figure, $C$ and $D$ are the trisection points of $AB$. At 8:00, Jia starts from $A$ and walks uniformly towards $B$, and at 8:12, Yi starts from $B$ and walks uniformly towards $A$. A few minutes later, Bing starts from $B$ and walks uniformly towards $A$; when Jia and Yi meet at point $C$, Bing is exactly at point $D$. When Jia and Bing meet at 8:30, Yi is exactly at $A$. Then, when did Bing start? $\qquad$ o'clock $\qquad$ minutes.
【Solution】Solution: (1) As shown in the figure, it takes Yi 18 minutes to travel from $B$ to $A$, divided into three segments, each taking 6 minutes. Jia and Yi meet at 8:24,

So Jia takes 24 minutes to travel from $A$ to $C$, $V_{\text {Jia: }} V_{\text {Yi }}=6: 24=1: 4$;
(2) Jia and Bing travel towards each other from $C$ and $D$, taking a total of 6 minutes. At this time, Yi also walks the same distance $C A$, so $V_{\text {Jia: }}$ : $V_{\text {Bing }}=1: 3$;
(3) Bing takes $6 \div 3 \times 4=8$ minutes to walk from $B$ to $D$, and the departure time from $B$ is 8:16.

Therefore, the answer is: 8:16