A train departs from Xi'an at 3:30 and arrives in Lanzhou at 10:30. The train travels 120 kilometers per hour. How many kilometers is it from Xi'an to Lanzhou?
一列火车3：30从西安出发，10：30到达兰州，火车每小时行驶120千米，西安到兰州多少千米？
<gadget id="calculator">120 * 7</gadget>
<output>840</output>

<result>840</result>