Two trains having lengths of 340 m and 360 m are running at speeds of 80 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: A
Explanation
The correct answer is Option 1 i.e. 4.2 .
Relative speed = 90 - 80 = 10 km/h = (10 × 1000) / 3600 = 25/9 m/s
Total length = 340 + 360 = 700 m
Time = Distance / Speed = 700 ÷ (25/9) = 700 × (9/25) = 252 seconds = 252/60
= 4.2 minutes