On a map with a scale of 1:4000000, the length of the road between A and B is measured to be 4.5 cm. A car travels from A to B for 3 hours, how many kilometers per hour does the car travel on average?
在比例尺为1：4000000的地图上，量得甲乙两地间的公路长4.5厘米．一辆汽车从甲地到乙地行了3小时，这辆汽车平均每小时行多少千米？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">4.5 / (1/4_000_000) / 100_000 / 3</gadget>
<output>60</output>

<result>60</result>