On a map with a scale of 1:400000, the distance between A and B is 5 cm; if the distance between A and B is measured on a map with a scale of 1:500000, what is the distance in centimeters between A and B?
在一幅比例尺是1：400000的地图上量得甲、乙两地的距离是5厘米；如果在比例尺是1：500000的地图上，甲、乙两地的图上距离是多少厘米．
<gadget id="calculator">1 / 400_000</gadget>
<output>1/400_000 = around 0.000002</output>

<gadget id="calculator">5 / (1/400_000)</gadget>
<output>2_000_000</output>

<gadget id="calculator">1 / 500_000</gadget>
<output>1/500_000 = around 0.000002</output>

<gadget id="calculator">2_000_000 * (1/500_000)</gadget>
<output>4</output>

<result>4</result>