A classmate goes to school with a speed of 240 m/min when starting out, and increases the speed by 50% when walking halfway. What is the average speed of this classmate going to school in m/min?
某同学上学，出发时速度为240米/分，当走到一半路程时，提速50%，该同学上学的平均速度为多少米/分．
<result>288</result>