cts - two trains run around a circular track at the rate of one round per hour and six rounds per hour respectively they start from the same point in the same direction at 730 am and they cross each other first at - skillgun

"Suppose two bodies are moving in the same direction at u m/s and v m/s, where u > v, then their relative speed is = (u - v) m/s."
Then, Relative speed between two trains = (6 - 1) = 5 rounds per hour.
And the time taken to complete one round at this speed = 1/5 hour = 60/5 = 12 minutes.
Therefore, they will meet after 12 minutes from when they start to run.
Two trains started at 7.30 a.m , they have met at 7.30 + 12 minutes = 7.42 a.m.