two runners run in the same direction along a circular track of 3 km in length. the faster runner overtakes the slower runner every one hour . find the speed of the slower runner if the faster one completes the length of track 2 minutes sooner than the other

Faster runner completes one more round than the slower runner in one hour. This means faster runner covers 3 km more than slower runner in one hour.
Let speed of slower runner be x km/hr
Therefore, speed of faster runner = (x+3)km/hr
Now, faster runner takes 2 minutes less than slower runner to cover 3 km i.e.
3/x - 3/(x+3) = 2/60

Solving this equation, we get x= 15km/hr
So, speed of slower runner= 15km/hr

my problem is what does overtaking means