Three fast, medium and slow cars start from the same place at the same time and chase a cyclist in front along the same road. The three cars take 6 minutes, 10 minutes, and 12 minutes to catch up with the cyclist respectively. Now we know that the express train travels 24 kilometers per hour, and the medium train travels 20 kilometers per hour, so how many kilometers per hour does the slow train travel?
快、中、慢三辆车同时从同一地点出发，沿同一条公路追赶前面的一个骑车人，这三辆车分别用6分、10分、12分钟追上骑车人．现在知道快车每小时行24千米，中车每小时行20千米，那么慢车每小时行多少千米？
<gadget id="calculator">14 + 5</gadget>
<output>19</output>

<result>19</result>