0Concept 3: Time when three objects meets for the first time When they are running around a circular track in the same direction.
Now, let us assume there are 3 persons A, B and C running in the same directions on 1000m track.
Speed of A = 30 m/s
Speed of B = 20 m/s
Speed of C = 10 m/s
Again the concept of relativity, the time when they will meet for the first time = time taken by the fastest runner to take one round over other runners.
Time taken by A to take one round over B , 1000/(30-20) = 100 s
Time taken by A to take one round over C, 1000/(30-10) = 50 s
Now the time after which they all three will meet = LCM(100,50) = 100.
Hence all three persons will meet after 100 seconds.
