Xiao Ming is running on a 360-meter runway. It is known that his speed is 5 m/s for the first half of the distance and 4 m/s for the second half of the distance. How long does it take him to run the second half of the distance?
小明在360米的跑道上跑步，已知他跑前一半路程的速度为5米/秒，跑后一半路程的速度为4米/秒，他跑后一半路程用了多少时间？
<gadget id="calculator">360 / 2 / 4</gadget>
<output>45</output>

<result>45</result>