The distance between the east and west cities is 254 kilometers. Two cars, A and B, drive out opposite each other. Car A travels 27 kilometers per hour. After driving for 2 hours, car B starts to set off at a speed of 23 kilometers per hour. How many hours after car B leaves, the two cars meet?
东西两城相距254千米，甲、乙两辆汽车相对开出，甲车每小时行27千米，先行2小时后，乙车开始出发，速度为每小时23千米．乙车出发几小时后两车相遇？
<gadget id="calculator">27 * 2</gadget>
<output>54</output>

<gadget id="calculator">254 - 54</gadget>
<output>200</output>

<gadget id="calculator">27 + 23</gadget>
<output>50</output>

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

<result>4</result>