Two trains A and B travel towards each other from two cities 470 kilometers apart. A train travels 38 kilometers per hour, and train B travels 40 kilometers per hour. Car B leaves first, and then car A leaves 2 hours later. How many hours later does car A meet car B?
甲、乙两列火车从相距470千米的两城相向而行，甲车每小时行38千米，乙车每小时行40千米．乙车先出发2小时后，甲车才出发．甲车行几小时后与乙车相遇？
<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">470 - 80</gadget>
<output>390</output>

<gadget id="calculator">40 + 38</gadget>
<output>78</output>

<gadget id="calculator">390 / 78</gadget>
<output>5</output>

<result>5</result>