railway inspector was working in the tunnel when he suddenly heard a train approaching the tunnel. He immediately looked at the road signs in the tunnel and knew that the distance between him and the tunnel entrance in the direction of the train was the full length of the tunnel (3 /7). Based on his experience, no matter which way he runs at the fastest speed, when the train arrives in front of him, it just leaves the tunnel. If the speed of the train is 70 kilometers per hour, what is the running speed of the road patrol worker in kilometers per hour?
一铁路巡道工正在隧道中工作，突然听到一列火车向隧道驶来，他立即看隧道内的路标，知道他与火车驶来方向的那端隧道口间的距离为隧道全长的(3/7)．凭他的经验，用最快的速度无论向哪一头跑，当火车到达他跟前时，都刚好离开隧道．如果火车速度为每小时70千米，请问巡道工奔跑的速度是每小时多少千米？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7) - (3/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/7) / 1</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">70 * (1/7)</gadget>
<output>10</output>

<result>10</result>