From City A to City B, the express train takes 20 hours, and the slow train takes 30 hours. The two cars depart from the two cities at the same time. When they meet, the slow train is still 1080 kilometers away from City A. How many miles is the distance between A and B?
从甲城到乙城，快车需要20小时，慢车需要30小时，两车同时从两城相对开出，相遇时慢车距甲城还有1080千米．甲、乙两城相距多少千米？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) + (1/30)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / (1/12)</gadget>
<output>12</output>

<gadget id="calculator">(1/20) * 12</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1_080 / (3/5)</gadget>
<output>1_800</output>

<result>1_800</result>