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

We have 18=2×3^{2} and 12 = 2^{2}×3

LCM is

Product of the greatest power of each prime factor involved in the numbers.

∴ L.C.M of 18 and 12 = 2^{2}×3^{2}=36

Hence Sonia and Ravi will meet after 36 min.