On the map of China with a scale of 1:4000000, the distance between the two places is 30 cm. What is the actual distance in kilometers between the two places?
在比例尺是1：4000000的中国地图上，量得两地的距离是30厘米，这两地的实际距离是多少千米．
<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</gadget>
<output>1_200</output>

<result>1_200</result>