The distance between the two places is 420 kilometers. Cars A and B drive from the two places at the same time. They meet each other in 3 hours. Car A travels 80 kilometers per hour. How many kilometers does car B travel per hour?
两地相距420千米，甲乙两车同时从两地相对开出，3小时相遇，甲车每小时行80千米，乙车每小时行多少千米？
<gadget id="calculator">420 / 3</gadget>
<output>140</output>

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

<result>60</result>