某校学生出去郊游,其学生队伍以7km/h的速度行进,队尾的通讯员以11km/h的速度赶到队伍前
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13.2min=0.22hr

L/(11-7)+L/(11+7)=0.22

L/4+L/18=0.22

9L+2L=18*0.22

L=18*0.22/11=0.36 Km=360m