A car and a truck drive toward each other from two cities 499 kilometers apart at the same time, and the car travels 52 kilometers per hour. After 5 hours, the distance between the two cars is still 39 kilometers. How many kilometers per hour does the truck travel?
一辆轿车和一辆卡车同时从相距499千米的两城相向而行，轿车每小时行52千米．5小时后两车仍相距39千米，卡车每小时行多少千米？
<gadget id="calculator">499 - 39</gadget>
<output>460</output>

<gadget id="calculator">460 / 5</gadget>
<output>92</output>

<gadget id="calculator">92 - 52</gadget>
<output>40</output>

<result>40</result>