On a map with a scale of 1:5,000,000, the distance between cities A and B is 6.4 centimeters. If a car drives from city A to city B at a speed of 80 kilometers per hour, how many hours will it take?
在比例尺是1：5000000的地图上，量得甲、乙两城市之间的距离是6.4厘米，如果一辆汽车以每小时80千米的速度从甲城开往乙城，需要几小时？
<gadget id="calculator">1 / 5_000_000</gadget>
<output>1/5_000_000 = around 0</output>

<gadget id="calculator">6.4 / (1/5_000_000) / 100_000 / 80</gadget>
<output>4</output>

<result>4</result>