On a map of 1:24000000, the distance between A and B is 3.5 cm. What is the actual distance in kilometers between the two places?
在一幅1：24000000的地图上量得甲乙两地的距离是3.5厘米，两地的实际距离是多少千米．
<gadget id="calculator">1 / 24_000_000</gadget>
<output>1/24_000_000 = around 0</output>

<gadget id="calculator">3.5 / (1/24_000_000) / 100_000</gadget>
<output>840</output>

<result>840</result>