Three bike riders ride around a circular path the first ride

Three bike riders ride around a circular path. the first rider circles the path in 12 minutes, the second in 18, and the third in 24 minutes. if they all start at the same place at the same time, when will they all meet again at the starting point?

Solution

We have three different numbers for our riders: 12, 18, and 24.
What we are looking for is a least common multiple.
LCM (12, 18, 24) = 72 minutes
So
the first rider travels 6 times around
the first rider travels 4 times around
the first rider travels 3 times around