Question

There is a circular path around a sports field. Preeti takes 18 minutes to drive one round of the field, while Suman takes 12 minutes for the same. Suppose they both start at the same point and at the same time, and go in the same direction. After how many minutes will they meet again at the starting point?

Answer 1

They will be meet again after LCM of both values at the starting point.
To get the LCM we have to factorize the number.
18        = 2 × 3 × 3
12        = 2 × 2 × 3
LCM    = 2 × 2 × 3 × 3 = 36 
Therefore, they will meet together at the starting point after 36 minutes.