Two trains are running towards each other, car A travels 72 kilometers per hour, and car B travels 36 kilometers per hour. It takes 13 seconds for the rear of the car to pass through his window. How many meters is the length of car A?
两列火车相向而行，甲车每小时行72千米，乙车每小时行36千米，两车错车时，乙车上一乘客发现：从甲车车头经过他的车窗时开始到甲车车尾经过他的车窗共用了13秒，求甲车的车长是多少米？
<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<gadget id="calculator">30 * 13</gadget>
<output>390</output>

<result>390</result>