His speed would be 2 km/hr.
Where S is speed, D is distance, and T is time, the equation "S=D/T" can be applied. You would substitute the information provided in this equation. However, since the time is in minutes but your answer must be in km per HOUR, you must convert it.
S=D/T
There is 60 minutes in an hour, so you would substitute 5/60 for T.
S=600km/5/60
S=2km/hr
