On a map with a scale of 1:3000000, the distance between A and B is 40 cm. Two cars leave opposite places A and B at the same time and meet each other after 12 hours. It is known that car A travels 48 kilometers per hour, how many kilometers per hour does car B travel?
在比例尺是1：3000000的地图上，量得甲、乙两地的距离是40厘米．两辆汽车同时从甲、乙两地相对开出，经过12小时相遇．已知甲车每小时行48千米，乙车每小时行多少千米？
<gadget id="calculator">1 / 3_000_000</gadget>
<output>1/3_000_000 = around 0</output>

<gadget id="calculator">40 / (1/3_000_000) / 100_000 / 12</gadget>
<output>100</output>

<gadget id="calculator">100 - 48</gadget>
<output>52</output>

<result>52</result>