On a map with a scale of 1:4000000, the distance between A and B is 30 cm. Two trains depart from A and B at the same time and meet each other in 12 hours. A train travels 55 kilometers per hour, and B train How many kilometers per hour?
在比例尺是1：4000000的地图上，量的甲、乙两地相距30厘米，两列火车同时从甲、乙两地相对开出，12小时相遇，甲车每小时行55千米，乙车每小时行驶多少千米？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">30 / (1/4_000_000) / 100_000 / 12</gadget>
<output>100</output>

<gadget id="calculator">100 - 55</gadget>
<output>45</output>

<result>45</result>