Cars A and B drive towards each other from two places at the same time. After 4.5 hours, the distance between the two cars is 9 kilometers. Car A travels 42 kilometers per hour, and car B travels 40 kilometers per hour.
甲乙两车从两地同时开出相向而行，4.5小时后两车相距9千米，甲车每小时行42千米，乙车每小时行40千米，两地相距多少千米？
<gadget id="calculator">42 + 40</gadget>
<output>82</output>

<gadget id="calculator">82 * 4.5</gadget>
<output>369</output>

<gadget id="calculator">369 + 9</gadget>
<output>378</output>

<result>378</result>