Xiao Ming and Xiao Hua practice running on a 400-meter circular track. They start from the same point at the same time and walk in the same direction. Xiao Ming runs 3.5 meters per second, and Xiao Hua runs 5.5 meters per second. How many seconds passed before the two met for the second time?
小明和小华在一个400米的环形跑道上练习跑步，两人同时从同一点出发，同向而行，小明每秒跑3.5米，小华每秒跑5.5米．经过多少秒，两人第二次相遇？
<gadget id="calculator">5.5 - 3.5</gadget>
<output>2</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">400 * 1</gadget>
<output>400</output>

<result>400</result>