Answer:
It will take 30 minutes
Explanation:
Here, we want to calculate the time it will take for the three friends to be at the starting point again
What we do here is to note the time it will take for each of the three friends to run a lap
That will be 6 , 3 and 5
What we now need to know the time is to find the lowest common multiple of the three amount of time
The lowest common multiple of 6,3 and 5 is 30
So the amount of time it will take the friends to be at the starting point again is 30 minutes