9. (12 points) Car A departs from location A to location B, while at the same time, Car B departs from location B to location A. Car A's speed is 80 kilometers per hour, and Car B's speed is 70 kilometers per hour. Car A stops at an intermediate point C, and 15 minutes later, Car B arrives at point C, at which time Car A resumes its journey. If both cars arrive at their destinations simultaneously, then the distance between A and B is $\qquad$ kilometers.
9. (12 points) Car A departs from location A to location B, while at the same time, Car B departs from location B to location A. Car A's speed is 80 kilometers per hour, and Car B's speed is 70 kilometers per hour. Car A stops at an intermediate point C, and 15 minutes later, Car B arrives at point C, at which time Car A continues its journey. If both cars arrive at their destinations simultaneously, then the distance between A and B is \qquad kilometers.

【Solution】Let the distance between A and B be $x$ kilometers.
15 minutes $=\frac{1}{4}$ hour
$$
\begin{array}{c}
x \div 80=x \div 70-\frac{1}{4} \\
\frac{1}{70} x-\frac{1}{80} x=\frac{1}{4} \\
\frac{1}{560} x=4 \\
x=140
\end{array}
$$

Answer: The distance between A and B is 140 kilometers.
Therefore, the answer is: 140.