and B travel from A to B at the same time. When A travels 1/3 of the whole journey, B travels 20 kilometers. When A arrives at B, B still has 1/7 of the journey. , how many kilometers is the distance between AB and AB?
甲乙两人同时从A地到B地，当甲行了全程的(1/3)时，乙行了20千米，当甲到达B地时，乙还有全程的(1/7)没有行，AB两地相距多少千米？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / (6/7) / (1/3)</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">20 * (7/2)</gadget>
<output>70</output>

<result>70</result>