∵v=st，∴跑200m用的时间：t1=s1v1=200m4m/s=50s，跑300m用的时间：t2=s2v2=300m3m/s=100s，休息时间t3=1min20s=80s，剩余路程用的时间：t4=s4v4=600m−200m−300m5m/s=20s，总时间：t=t1+t2+t3+t4=50s+100s+80s+20...