Three bodies X, Y and Z start moving around a circular track of length 960m from the same point simultaneously in the same direction at speeds of 12 m/s, 20 m/s and 36 m/s respectively. When will they meet for the first time after they started moving?
Options.
A) 240 seconds
B) 120 seconds
C) 60 seconds
D) 180 seconds
E) 100 seconds
If they all meet after T seconds, it means they covered the distances 12T, 20T, and 36T 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 960m. So, 8T, 16T, and 24T must all be multiples of 960. 8T multiple of 960 means T multiple of 120. The smallest T with this property is 120 and is on the list of answers.   Answer 120 seconds.
<result>B</result>
Three bodies X, Y and Z start moving around a circular track of length 960m from the same point simultaneously in the same direction at speeds of 12 m/s, 20 m/s and 36 m/s respectively. When will they meet for the first time after they started moving?