3. (10 points) Car $A$ departs from station A heading to station B, while cars $B$ and $C$ depart from station B heading towards station A at the same time. On the way, $A$ meets $B$ 20 minutes after meeting $C$. It is known that the speeds of $A$, $B$, and $C$ are 90 km/h, 80 km/h, and 60 km/h, respectively. The distance between station A and station B is $\qquad$ km.