The distance between A and B is 600 kilometers. Car A starts from A for several hours before B starts from B. The two cars are heading towards each other. It is known that car A travels 40 kilometers per hour and car B travels 60 kilometers per hour. In order for car B to encounter car A 4.4 hours after departure, how many hours does car A need to start first?
A、B两地相距600千米，甲车先从A第出发若干小时后，乙车才从B第出发．两车相向而行．已知甲车每小时行40千米，乙车每小时行60千米．要使乙车在出发后4.4小时后遇到甲车，甲车需要先出发几小时？
<gadget id="calculator">40 + 60</gadget>
<output>100</output>

<gadget id="calculator">100 * 4.4</gadget>
<output>440</output>

<gadget id="calculator">600 - 440</gadget>
<output>160</output>

<gadget id="calculator">160 / 40</gadget>
<output>4</output>

<result>4</result>