Two cars A and B drive towards each other from Bazhong and Chengdu at the same time. Car A travels 45 kilometers per hour, and car B travels 42 kilometers per hour. The two cars meet at a distance of 9 kilometers from the midpoint. How many kilometers is the distance between Bazhong and Chengdu?
甲乙两辆汽车同时从巴中和成都两地相向开出，甲车每小时行45千米，乙车每小时行42千米，两车在距离中点9千米处相遇．巴中和成都两地相距多少千米？
<gadget id="calculator">45 + 42</gadget>
<output>87</output>

<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<gadget id="calculator">45 - 42</gadget>
<output>3</output>

<gadget id="calculator">18 / 3</gadget>
<output>6</output>

<gadget id="calculator">87 * 6</gadget>
<output>522</output>

<result>522</result>