Two people, A and B, go from the east city to the west city at the same time. A travels 120 meters per minute, and B travels 80 meters per minute. After reaching the west city, A immediately returns to the east city and meets B at a distance of 700 meters from the west city. What is the distance between the east and west cities? rice?
甲、乙二人同时从东城去西城，甲每分钟行120米，乙每分钟行80米，甲到达西城后立即返回东城，在离西城700米处与乙相遇，东、西两城相距多少米？
<gadget id="calculator">120 - 80</gadget>
<output>40</output>

<gadget id="calculator">2 / 40</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">700 * (1/20) * 80</gadget>
<output>2_800</output>

<gadget id="calculator">2_800 + 700</gadget>
<output>3_500</output>

<result>3_500</result>