A freight train and a passenger train depart from two places 504 kilometers apart at the same time, and meet each other in 4.5 hours. The passenger car travels 64 kilometers per hour, how many kilometers per hour does the truck travel?
一列货车和一列客车同时从相距504千米的两地相对开出，4.5小时相遇．客车每小时行64千米，货车每小时行多少千米？
<gadget id="calculator">504 / 4.5</gadget>
<output>112</output>

<gadget id="calculator">112 - 64</gadget>
<output>48</output>

<result>48</result>