The train from Nanjing to Shanghai originally travels 120 kilometers per hour and takes 3 hours to arrive. After the speed of the train is increased, the speed of the train reaches 180 kilometers per hour. How long does it take to take the train from Nanjing to Shanghai?
火车从南京开往上海，原来每小时行驶120千米，要3小时才能到达．火车提速后，火车的速度达到每小时180千米，现在从南京做火车到上海需要多长时间？
<gadget id="calculator">3 / 180</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">120 * (1/60)</gadget>
<output>2</output>

<result>2</result>