Xiaojun and Xiaoliang set off from the same place facing each other on the 400-meter circular runway, and they met for the first time after 50 seconds. Xiaojun runs 4.5 meters per second, how many meters does Xiaoliang run per second?
小军和小亮在400米的环形跑道上，从同一地点相背出发，经过50秒后两人第一次相遇．小军每秒跑4.5米，小亮每秒跑多少米？
<gadget id="calculator">400 / 50</gadget>
<output>8</output>

<gadget id="calculator">8 - 4.5</gadget>
<output>3.5</output>

<result>3.5</result>