A and B go around a circular track of length 900m on a cycle at speeds of 36 kmph and 54 kmph. After how much time will they meet for the first time at the starting point?
Choose the correct answer:
A) 120 sec  B) 165 sec  C) 186 sec  D) 180 sec  E) 168 sec
Time taken to meet for the first time at the starting point   = LCM { length of the track / speed of A , length of the track / speed of B}   = LCM { 900/ (36 * 5/18) , 900/ (54 * 5 /18) }   = LCM (90, 60)   =180 sec.   Answer:180 sec
<result>D</result>
A and B go around a circular track of length 900m on a cycle at speeds of 36 kmph and 54 kmph. After how much time will they meet for the first time at the starting point?