Two trains having lengths of 210 m and 440 m are running at speeds of 60 km/h and 90 km/h, respectively, in the same direction. The time taken (in minutes) by the faster train, coming from behind, to completely cross the other train is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 1.3.
Relative speed = 90 - 60 = 30 km/h
Convert to m/s = 30 × 5/ 18 = 25/3 m/s
Distance = 210 + 440 = 650 m
Time = Distance / Speed = 650 / (25/3) = 650 × 3 / 25 = 78 s
Convert to minutes = 78 / 60 = 13/10 min = 1.3 min