Two cars, A and B, depart from places A and B at the same time, respectively. Car A travels 70 km per hour, and car B travels 60 km per hour. The midpoint is 20km, how many kilometers is the distance between A and B?
甲、乙两车分别从A、B两地同时出发相对开出，甲车每小时行70km，乙车每小时行60km，当甲车行完全程的(2/3)时，乙车已超过中点20km，A，B两地间的路程是多少千米？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">70 / 60</gadget>
<output>7/6 = around 1.166667</output>

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

<gadget id="calculator">(2/3) * (6/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(4/7) - (1/2)</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">20 / (1/14)</gadget>
<output>280</output>

<result>280</result>