The distance between A and B is 312 kilometers. A passenger car leaves from A, and a freight train leaves from B at the same time. After 3 o'clock, the two cars meet. The passenger car travels 54 kilometers per hour, how many kilometers per hour does the truck travel?
甲、乙两地相距312千米，一列客车从甲地开出，一列货车同时从乙地开出，3时后两车相遇．客车每时行驶54千米，货车每时行驶多少千米？
<gadget id="calculator">312 / 3</gadget>
<output>104</output>

<gadget id="calculator">104 - 54</gadget>
<output>50</output>

<result>50</result>