6. (10 points) Cars A and B start from locations $A$ and $B$ respectively at the same time, moving towards each other at a constant speed, and meet at a point 60 kilometers from $A$. After meeting, the two cars continue to move forward, reach $B$ and $A$ respectively, and immediately return on the same route, meeting again at a point 50 kilometers from $B$. The distance between $A$ and $B$ is $\qquad$ kilometers.
【Analysis】The ratio of distances when they meet is equal to the ratio of their speeds, so we can set up a relationship. Let the distance between $A$ and $B$ be $S$. The first time they meet, A has walked 60 kilometers, and B has walked $S-60$ kilometers. The second time they meet, A has walked another $S-60+50$ kilometers, and B has walked another $60+S-50$ kilometers. This allows us to find the value of $S$.
【Solution】Solution: According to the analysis, let the distance between $A$ and $B$ be $S$. The first time they meet, A has walked 60 kilometers, and B has walked $S-60$ kilometers,

The second time they meet, A has walked another $S-60+50$ kilometers, and B has walked another $60+S-50$ kilometers, so: $\frac{60}{S-60}=\frac{S-60+50}{60+S-50}$,
Solving this, we get: $S=130$.
Therefore, the answer is: 130.