Two trains travelling to opposite directions cross each other in 25 seconds. If the length of both the trains is 250 m each and the speed of one of them is 45 km/hr, what would be the speed of the other train?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 27 km/hr .
Length of both trains = 250 m each → total length = 500 m
Time to cross = 25 seconds
Speed of first train = 45 km/h = (45 × 1000) / 3600 = 12.5 m/s
Let speed of second train = x m/s
Total speed = (12.5 + x) m/s
Distance = 500 m
Time = 25 s
Use: distance = speed × time
500 = (12.5 + x) × 25
500 = 312.5 + 25x
25x = 187.5
x = 7.5 m/s
Convert x to km/h:
7.5 × 18 / 5 = 27 km/h