On a map with a scale of 1:2000000, the distance from Zhongshan to Guangzhou is 3.5 centimeters. What is the actual distance from Zhongshan to Guangzhou in kilometers?
在一幅比例尺是1：2000000的地图上，量得中山到广州的距离是3.5厘米，中山到广州的实际距离是多少千米．
<gadget id="calculator">1 / 2_000_000</gadget>
<output>1/2_000_000 = around 0</output>

<gadget id="calculator">3.5 / (1/2_000_000) / 100_000</gadget>
<output>70</output>

<result>70</result>