11. (6 points) Person A and Person B start from locations $A$ and $B$ respectively and walk towards each other at the same time. Person B's speed is $\frac{3}{2}$ of Person A's speed. After they meet, they continue to their respective destinations, with Person A reaching $B$ and Person B reaching $A$, and then they immediately return. It is known that the location of their second meeting is 20 kilometers away from the location of their first meeting. Therefore, the distance between $A$ and $B$ is $\qquad$ kilometers.
11. (6 points) Person A and Person B start from points $A$ and $B$ respectively at the same time and walk towards each other. Person B's speed is $\frac{3}{2}$ of Person A's speed. After they meet, they continue to walk, with Person A reaching point $B$ and Person B reaching point $A$, then they immediately turn back. It is known that the distance between the second meeting point and the first meeting point is 20 kilometers. Therefore, the distance between points $A$ and $B$ is $\qquad$ kilometers.
$$
\begin{array}{l}
\text { [Solution] } 20 \div\left[\frac{3}{2+3}-\left(\frac{2 \times 3}{2+3}-1\right)\right] \\
=20 \div\left[\frac{3}{5}-\frac{1}{5}\right], \\
=20 \times \frac{5}{2}, \\
=50 \text { (kilometers); }
\end{array}
$$

Therefore, the answer is: 50 kilometers.