The circular runway of the school playground is 200 meters long. Xiao Wang and Xiao Li run counterclockwise from the starting line at the same time. Xiao Wang runs 7.5 meters per second and Xiao Li runs 5.5 meters per second. How many seconds does it take for the two to meet for the first time?
学校操场的环形跑道长200米，小王和小李两人同时从起跑线沿逆时针方向跑步，小王每秒7.5米，小李每秒跑5.5米，经过多少秒两人第一次相遇？
<gadget id="calculator">7.5 - 5.5</gadget>
<output>2</output>

<gadget id="calculator">200 / 2</gadget>
<output>100</output>

<result>100</result>