In a 1200 m circular race A and B start at the same time from the same position in the same direction at speeds of 18 km/h and 27 km/h respectively. In how much time after the start of race will they meet for the first time on the track?

Given:
Speed of A = 18 km/h
Speed of B = 27 km/h
Length of the track = 1200 m
Formula Used:
Time to meet for the first time = Length of track / Relative speed

1 km/hr = $$\frac{5}{18}\ \ m/sec$$​​

Solution:
Relative speed = 27 km/h - 18 km/h = 9 km/h  = 2.5 m/s
Time to meet for the first time = 1200 m / 2.5 m/s = 480 seconds
The time after which they will meet for the first time on the track is 480 seconds.​​