Ali and Badal start from the same position and at the same time in a 1200 m circular race, with speeds of 27 km/h and 45 km/h, respectively. Find after how much time they will meet again on the track for the first time when they are both running in the same direction.

240 seconds

Relative speed (when both moves in same direction ) = 45 - 27 = 18 km/h

18 km/h = 18 × \(\frac{5}{18}\) m/sec = 5 m/sec

Time taken by them to meet each other = \(\frac{1200}{5}\)

= 240 seconds