Two cars A and B start from the east and west cities at the same time. Car A meets car B at a place 20 kilometers beyond the midpoint. It is known that the ratio of the distance traveled by car A to the distance traveled by car B is 7:6. How many kilometers are the two cities apart?
甲乙两车同时从东、西两城出发，甲车在超过中点20千米的地方与乙车相遇，已知甲车所走的路程与乙车所行路程的比是7：6，东西两城相距多少千米？
<gadget id="calculator">20 * 7</gadget>
<output>140</output>

<gadget id="calculator">20 * 6</gadget>
<output>120</output>

<gadget id="calculator">140 + 120</gadget>
<output>260</output>

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

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

<gadget id="calculator">(1/2) * 6</gadget>
<output>3</output>

<gadget id="calculator">7 - (7/2) - 3</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">260 / (1/2)</gadget>
<output>520</output>

<result>520</result>