Two trains depart from A and B at the same time, and meet at a distance of 50 kilometers from the midpoint after 5 hours. It is known that the speed of the slow train is that of the express train (5/7). How many kilometers are the distance between A and B?
两列火车从甲乙两地同时相对开出，5小时后在距中点50千米处相遇，已知慢车的速度是快车的(5/7)，甲乙两地相距多少千米？
<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">1 - (5/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">100 / 5 / (2/7)</gadget>
<output>70</output>

<gadget id="calculator">70 * 5 * 2</gadget>
<output>700</output>

<gadget id="calculator">700 - 100</gadget>
<output>600</output>

<result>600</result>