The distance between A and B is 504 km. A train of passenger cars and a train of freight trains pass from the two cities at the same time. It is known that the average speed of the passenger train is 60 km per hour. The bus breaks down on the way and stops for 1 hour. After the two cars have passed for 3 hours, the two cars meet, how many kilometers per hour does the truck travel?
甲、乙两城相距504千米，一列客车和一列货车同时从两城对开，已知客车平均每小时行60千米，途中由于客车发生故障，停了1小时．两车经过3小时后两车相遇，问货车每小时行多少千米？
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<gadget id="calculator">504 - 120</gadget>
<output>384</output>

<gadget id="calculator">384 / 3</gadget>
<output>128</output>

<result>128</result>