Three race cars driven by James, Myles and Samantha start moving around a circular race track of length 1500m from the same point simultaneously in the same direction at speeds of 15 m/s, 25 m/s and 45 m/s respectively. When will they meet for the first time after they started moving?  Answers:
A) 540 seconds  B) 240 seconds  C) 200 seconds  D) 300 seconds  E) 150 seconds
If they all meet after T seconds, it means they covered the distances 15T, 25T, and 45T respectively.   Since they all arrive to the same spot, it means that the differences taken pairwise between the distances must be positive integer multiples of the length of the track, which is 1500m. So, 10T, 20T, and 30T must all be multiples of 1500. 10T multiple of 1500 means T multiple of 150. The smallest T with this property is 150 and is on the list of answers.   Answer 150 seconds.
<result>E</result>
Three race cars driven by James, Myles and Samantha start moving around a circular race track of length 1500m from the same point simultaneously in the same direction at speeds of 15 m/s, 25 m/s and 45 m/s respectively. When will they meet for the first time after they started moving?