On a map with a scale of 1:4,000,000, the length of the railway line from Nanjing to Shanghai is 7.5 cm. Calculated according to the speed of the high-speed train at 200 kilometers per hour, how many hours does it take for the train departing from Shanghai to arrive at Nanjing?
在比例尺是1：4000000的地图上，量得南京到上海的铁路线长7.5厘米．按照高速列车时速200千米计算，那么从上海出发的列车经过多少小时到达南京．
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">7.5 / (1/4_000_000) / 100_000 / 200</gadget>
<output>1.5</output>

<result>1.5</result>