Two trains, 200 m and 250 m long, are moving in the same direction at speeds of 80 km/hr and 60 km/hr, respectively. How long (in seconds) will it take for the faster train to completely pass the slower one?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 81 .
Length of faster train = 200 m
Length of slower train = 250 m
Speed of faster train = 80 km/hr
Speed of slower train = 60 km/hr
Relative speed = 80 − 60 = 20 km/hr
Convert relative speed to m/s, 20 × 5/18 = 5.56 m/s
Total distance to be covered = 200 + 250 = 450 m
Time = 450 ÷ 5.56 = 81 seconds