On a 1:40000000 map, the distance between the airports of A and B is 4.5 centimeters. How many hours does it take for an airplane to fly from airport A to airport B at a speed of 750 kilometers per hour?
在一幅1：40000000的地图上，量得甲乙两地机场距离为4.5厘米，一架飞机以每小时750千米的速度从甲机场飞往乙机场，需要几小时？
<gadget id="calculator">1 / 40_000_000</gadget>
<output>1/40_000_000 = around 0</output>

<gadget id="calculator">4.5 / (1/40_000_000) / 100_000 / 750</gadget>
<output>2.4</output>

<result>2.4</result>