A truck and a passenger car drive toward each other from two places 535.5 kilometers apart. The truck travels 78.5 kilometers per hour, and the passenger car travels 74.5 kilometers per hour. After how many hours do the two vehicles meet on the way?
一辆货车和一辆客车从相距535.5千米的两地相向开出，货车每小时行78.5千米，客车每小时行74.5千米，两车经过几小时在途中相遇？
<gadget id="calculator">78.5 + 74.5</gadget>
<output>153</output>

<gadget id="calculator">535.5 / 153</gadget>
<output>3.5</output>

<result>3.5</result>