On a map with a scale of 1:4,000,000, the distance between Kunming and Luoping is measured as 15cm. Two trains depart from the two places at the same time. A train travels an average of 80 kilometers per hour, and the speed of B train is that of A train. (7/8), after how many hours did the two trains meet?
在比例尺1：4000000的地图上，量得昆明到罗平之间的距离为15cm，两列火车分别从两地同时开出，甲车平均每小时行80千米，乙车的速度是甲车的(7/8)，两列火车经过几小时相遇？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">80 * (7/8)</gadget>
<output>70</output>

<gadget id="calculator">80 + 70</gadget>
<output>150</output>

<gadget id="calculator">15 / (1/4_000_000) / 100_000 / 150</gadget>
<output>4</output>

<result>4</result>