If the speed of the train between A and B is increased from 200 km/h to 300 km/h, the running time will be shortened by 2 hours. What is the distance between A and B in kilometers?
若往返于甲、乙两城之间的列车的速度由原来的200千米/时提高到300千米/时，运行时间将缩短2小时，则甲、乙两城相距多少千米．
<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<gadget id="calculator">300 - 200</gadget>
<output>100</output>

<gadget id="calculator">600 / 100</gadget>
<output>6</output>

<gadget id="calculator">200 * 6</gadget>
<output>1_200</output>

<result>1_200</result>