82. A vanguard unit of the PLA sets off from location $A$ via location $B$ to reach location $C$. Three hours later, the unit is urgently dispatched to send a communicator by car to make contact. It is known that the communicator's car speed is 20 kilometers per hour faster than the vanguard unit's speed. The vanguard unit reaches location $B$ 2 hours before the communicator arrives at $B$. When the communicator reaches $B$, the vanguard unit has already arrived at $C$. It is known that the distance between $B$ and $C$ is 120 kilometers. How far is it from $A$ to $B$ in kilometers?
Reference answer: 240