bus and a car are traveling towards each other at the same time from two places 200 kilometers apart, the bus travels 20 kilometers per hour, and the car travels 30 kilometers per hour. Q: How many hours later will the two cars meet?
一辆公共汽车和一辆小轿车同时从相距200千米的两地相向而行，公共汽车每小时行20千米，小轿车每小时行30千米．问：几小时后两车相遇？
<gadget id="calculator">20 + 30</gadget>
<output>50</output>

<gadget id="calculator">200 / 50</gadget>
<output>4</output>

<result>4</result>