On a map of 1:4000000, Xiao Ming measured that the distance from Yangzhou to Beijing is 30 centimeters. During the summer vacation, he wants to take the train to Beijing to watch the Olympic Games. The train is 120 kilometers per hour.
小明在一幅1﹕4000000的地图上，量得扬州到北京的距离是30厘米，暑假里，他想乘火车去北京看奥运会，火车每小时120千米，他需坐多少小时的火车．
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">30 / (1/4_000_000) / 100_000 / 120</gadget>
<output>10</output>

<result>10</result>