On a map with a scale of 1:6000000, the length of the railway line between A and B is measured to be 20 cm. Two passenger and freight trains depart from A and B oppositely at the same time. After 8 hours, the two trains meet. It is known that the passenger train travels 90 kilometers per hour. How many kilometers per hour does the freight train travel?
在比例尺是1：6000000的地图上，量得甲、乙两地间的铁路线长为20厘米．客货两列火车同时从甲、乙两地相对开出，经过8小时两列火车相遇，已知客车每小时行90千米，货车每小时行多少千米？
<gadget id="calculator">1 / 6_000_000</gadget>
<output>1/6_000_000 = around 0</output>

<gadget id="calculator">20 / (1/6_000_000) / 100_000 / 8</gadget>
<output>150</output>

<gadget id="calculator">150 - 90</gadget>
<output>60</output>

<result>60</result>