The distance between A and B stations is 690 kilometers. A freight train departs from station A to station B at a speed of 45 kilometers per hour. After 2 hours, a passenger train departs from station B to station A at a speed of 55 kilometers per hour. The passenger car Encounter the van after hours of driving?
AB两站相距690千米，一列货车以每小时45千米的速度从A和向B站开出，2小时后一列客车以每小时55千米的速度从B站向A站开出，客车开出几小时后与货车相遇？
<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<gadget id="calculator">690 - 90</gadget>
<output>600</output>

<gadget id="calculator">55 + 45</gadget>
<output>100</output>

<gadget id="calculator">600 / 100</gadget>
<output>6</output>

<result>6</result>