Two people, A and B, are walking toward each other from two places 400 kilometers apart. A travels 40 kilometers per hour. Two hours after departure, B starts. B travels 60 kilometers per hour. Question: How many hours after A starts and meets B? ?
甲、乙二人从相距400千米的两地相向而行，甲每小时行40千米，出发二小时后乙出发，乙每小时行60千米，问：甲出发几小时后与乙相遇？
<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">400 - 80</gadget>
<output>320</output>

<gadget id="calculator">40 + 60</gadget>
<output>100</output>

<gadget id="calculator">320 / 100</gadget>
<output>16/5 = around 3.2</output>

<gadget id="calculator">(16/5) + 2</gadget>
<output>26/5 = around 5.2</output>

<result>26/5 = around 5.2</result>