The distance between A and B is 320 kilometers. Cars A and B drive from the two places at the same time. Car A travels 38 kilometers per hour, and car B travels 42 kilometers per hour. How many hours later will the two cars meet?
A、B两地相距320千米，甲、乙两车同时从两地相对开出，甲车每小时行38千米，乙车每小时行42千米，几小时后两车相遇？
<gadget id="calculator">38 + 42</gadget>
<output>80</output>

<gadget id="calculator">320 / 80</gadget>
<output>4</output>

<result>4</result>