Two trains, A and B, are traveling towards each other at a distance of 534 kilometers. A travels 60 kilometers per hour. After A leaves for 0.5 hours, B does not leave. B travels 66 kilometers per hour. After several hours, the two trains meet?
甲、乙两列火车从相距534千米处相向行驶，甲每小时行60千米，甲开出0.5小时后，乙车才开出，乙车每小时行66千米，经过几小时两车相遇？
<gadget id="calculator">60 * 0.5</gadget>
<output>30</output>

<gadget id="calculator">534 - 30</gadget>
<output>504</output>

<gadget id="calculator">60 + 66</gadget>
<output>126</output>

<gadget id="calculator">504 / 126</gadget>
<output>4</output>

<result>4</result>