On a map with a scale of 1:4,000,000, the distance between A and B is 20 centimeters. Two trains depart from A and B at the same time. Train A travels 54 kilometers per hour, and train B travels per hour. Traveling 46 kilometers, how many hours will the two cars meet?
在比例尺是1：4000000的地图上，量得A、B两地的距离是20厘米，两列火车同时从A、B两地相对开出，甲车每小时行54千米，乙车每小时行46千米，几小时后两车相遇？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">54 + 46</gadget>
<output>100</output>

<gadget id="calculator">20 / (1/4_000_000) / 100_000 / 100</gadget>
<output>8</output>

<result>8</result>