On a map with a scale of 1:4000000, the distance between A and B is 10 cm. Two trains depart from A and B at the same time and meet each other in 4 hours. It is known that A train travels 55 kilometers per hour. How many kilometers does car B travel per hour?
在比例尺是1：4000000的地图上，量得甲、乙两地相距10厘米，两列火车同时从甲、乙两地相对开出，4小时相遇，已知甲车每小时行55千米，乙车每小时行多少千米？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">10 / (1/4_000_000) / 100_000 / 4</gadget>
<output>100</output>

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

<result>45</result>