If the distance between A and B is 20 cm on a 1:300000 map, what is the actual distance in kilometers?
在1：300000的地图上量得A、B两地的距离是20厘米，则实际距离是多少千米．
<gadget id="calculator">1 / 300_000</gadget>
<output>1/300_000 = around 0.000003</output>

<gadget id="calculator">20 / (1/300_000) / 100_000</gadget>
<output>60</output>

<result>60</result>