On a map with a scale of 1:4000000, the measured distance between A and B is 4.5 cm. A car drives from A to B at a speed of 30 kilometers per hour. How long does it take to arrive?
在比例尺是1：4000000的地图上，量的甲、乙两地的距离是4.5厘米，一辆汽车以每小时30千米的速度从甲地开往乙地，几小时到达？
<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 / 30</gadget>
<output>6</output>

<result>6</result>