The speed of the small army = 50m/min,

The speed of the dog = 200m/min, which is four times that of Xiaojun.

In time, Xiaojun and the dog start and stop at the same time, so the time is the same.

The distance traveled by the small army =600 (meters),

Then the distance of the dog =600*4=2400 (meters)

600*(200/50)=2400 (m)

Over! NBUZW