A train travels 270 kilometers in 3 hours. At this speed, the railway from Nanchang to Shanghai is 810 kilometers long. How many hours will it take to travel?
一列火车3小时行驶270千米，照这样的速度，南昌到上海的铁路长810千米，要行驶多少小时？
<gadget id="calculator">270 / 3</gadget>
<output>90</output>

<gadget id="calculator">810 / 90</gadget>
<output>9</output>

<result>9</result>