Two trains having lengths of 170 m and 480 m are running at speeds of 70 km/h and 80 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: D
Explanation
The correct answer is option 4 i.e.3.9.
Length of trains = 170 + 480 = 650 m
Relative speed = 80 − 70 = 10 km/h = (10 × 1000) / 3600 = 25/9 m/s
Time = Distance / Speed = 650 ÷ (25/9) = 650 × 9 / 25 = 234 s = 234/60 = 3.9 minutes