It is known that the distance between A and B is 490 kilometers. Two trucks A and B drive from A and B at the same time, and meet each other for 3.5 hours. The truck A travels 60 kilometers per hour, how many kilometers does the truck B travel per hour?
已知A、B两地间的路程是490千米．甲、乙两辆货车同时从A、B两地开出，相向而行3.5小时相遇，甲货车每小时行60千米，乙货车每小时行多少千米？
<gadget id="calculator">490 / 3.5</gadget>
<output>140</output>

<gadget id="calculator">140 - 60</gadget>
<output>80</output>

<result>80</result>