A and B go around a circular track of length 600 m 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 option
A) 120
B) 775
C) 555
D) 288
E) 278

Rationale: "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 { 600 / ( 36 * 5 / 18 ) , 600 / ( 54 * 5 / 18 ) } = lcm ( 60 , 40 ) = 120 sec . answer : a"
Answer: A