A train travels from A to B at a speed of 70 km/h for 3 hours. Then on a map with a scale of 1:5000000, what is the length of the railway between A and B?
一列火车以每小时70千米的速度从甲地开往乙地，行驶了3小时．那么在比例尺1：5000000的地图上，甲、乙两地之间的铁路长是多少？
<gadget id="calculator">1 / 5_000_000</gadget>
<output>1/5_000_000 = around 0</output>

<gadget id="calculator">70 * 3 * 100_000 * (1/5_000_000)</gadget>
<output>21/5 = around 4.2</output>

<result>21/5 = around 4.2</result>