On a map of China with a scale of 1:30,000,000, the length of the railway from Lianyungang to Urumqi via Lanzhou is about 12 centimeters. How long does it take for a train to depart from Lianyungang to Urumqi at an average speed of 120 kilometers per hour? (Does not count the stopover time on the way)
在比例尺是1：30,000,000的中国地图上，量得连云港经兰州到乌鲁木齐的铁路长约12厘米．一列火车以平均每时120千米的速度从连云港出发去乌鲁木齐，约需多少时？(不计途中靠站停留的时间)
<gadget id="calculator">1 / 30_000_000</gadget>
<output>1/30_000_000 = around 0</output>

<gadget id="calculator">12 / (1/30_000_000) / 100_000 / 120</gadget>
<output>30</output>

<result>30</result>