On a map with a scale of 1:2500000, the distance between Nanjing and Yangzhou is 3.8 cm. It takes 1.9 hours for a car to drive from Nanjing to Yangzhou. How many kilometers does this car travel per hour?
在一幅比例尺为1：2500000的地图上，量得南京与扬州之间的距离是3.8厘米．一辆汽车从南京开往扬州共用了1.9时，这辆汽车每小时行多少千米？
<gadget id="calculator">1 / 2_500_000</gadget>
<output>1/2_500_000 = around 0</output>

<gadget id="calculator">3.8 / (1/2_500_000) / 100_000 / 1.9</gadget>
<output>50</output>

<result>50</result>