passenger train and a freight train depart from A and B oppositely at the same time. When the two trains meet, the passenger train has traveled 70% of the journey, and the freight train is still 230 kilometers away from the midpoint of the two places. It is known that it takes 20 hours for the bus to travel the entire distance, how many kilometers does the bus travel per hour?
一列客车和一列货车同时从甲乙两地相对开出，当两列火车相遇时，客车走了全程的70%，货车距离两地的中点还有230千米．已知客车走完全程要用20小时，客车每小时行多少千米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/2) - (3/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">230 / (1/5) / 20</gadget>
<output>115/2 = around 57.5</output>

<result>115/2 = around 57.5</result>