The express train and the local train depart from the east and west stations at the same time, and meet for the first time at a distance of 10 kilometers west of the midpoint. The distance between East Station and East Station accounts for (2/7) of the distance between East and West Stations. How many kilometers is the distance between the east and west stations?
快车和慢车同时从东西两站相对开出，第一次在距中点西侧10千米处相遇，相遇后两车以原速前进，到达对方出发地后立即返回，第二次相遇时距东站的距离占东西两站间距离的(2/7)．东西两站相距多少千米？
<gadget id="calculator">10 * 2 * 3</gadget>
<output>60</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(5/7) - (2/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">60 / (3/7)</gadget>
<output>140</output>

<result>140</result>