On a traffic map with a scale of 1:5,000,000, the Lian-Xu Expressway is 4 cm long. How long does it take for a car to drive from Lianyungang to Xuzhou at a speed of 80 kilometers per hour?
在一幅比例尺是1：5000000的交通地图上量得连徐高速公路长4厘米．一辆汽车以每小时80千米的速度从连云港开往徐州，多少小时到达？
<gadget id="calculator">1 / 5_000_000</gadget>
<output>1/5_000_000 = around 0</output>

<gadget id="calculator">4 / (1/5_000_000) / 100_000 / 80</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>