Question

Three bus services A, B and C arrive at a station. Service A arrives at the station every 20 minutes, service B arrives every 45 minutes and service C arrives every 1 hour. All three buses arrive at the station together at 9 a.m. At what time will the three buses next arrive at the station

Answer 1

Step-by-step explanation:

Here A repeats after every 20 mins so lcm(lowest common multiple) of time taken of A and C is 1 hour(60 mins)

Next lcm of A and B is 180 mins

So we can conclude that the lcm of time of A,B and C is 180 mins (or 3 hours)

so the final ans is 12 pm