A train departs from Wuhan to a certain city, departs at 6:30 p.m., and arrives at a certain city at 3:30 a.m. the next day. It is known that the train travels 90 kilometers per hour. How many kilometers are the distance between these two cities?
一列火车从武汉开往某城市，下午6点30分发车，于次日凌晨3点30分到达某城市．已知这列火车每小时行90千米，这两个城市相距多少千米？
<gadget id="calculator">90 * 9</gadget>
<output>810</output>

<result>810</result>