Find the rate in which both balls make one full rotation around the track.
Ball A:
[tex]120 / 4 = 30[/tex]
It takes 30 seconds for Ball A to make a full rotation.
Ball B:
[tex]60 / 3 = 20[/tex]
It takes 20 seconds for Ball B to make a full rotation.
Find the least common multiple of 20 and 30 to find the time at which they'll meet.
Multiples of 20: {20,40,60}
Multiples of 30: {30,60}
60 is the least common multiple of both 20 and 30.
The balls will meet again at 60 seconds.
