On a map with a scale of 1:2000000, the length of the road line between A and B is 16 cm. A bus departs from A at 10:20 am and arrives at B at 2:20 pm. How many kilometers per hour does the bus travel on average?
在一张比例为1：2000000的地图上量得甲、乙两地的公路线长为16厘米．一辆客车在上午10：20从甲地出发，下午2：20到达乙地，这辆客车平均每小时行多少千米？
<gadget id="calculator">1 / 2_000_000</gadget>
<output>1/2_000_000 = around 0</output>

<gadget id="calculator">16 / (1/2_000_000) / 100_000 / 4</gadget>
<output>80</output>

<result>80</result>