Two trains are approaching each other on parallel tracks. Their lengths are 700 m and 400 m, respectively. The speed of the first train is 95 km/hr and that of the second train is 125 km/hr. The time required by the trains to cross each other is :
20 seconds
18 seconds
16 seconds
14 seconds
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CISF-AC-EXE – 2023
– Speed of first train = 95 km/hr.
– Speed of second train = 125 km/hr.
– Relative speed = 95 + 125 = 220 km/hr.
– To convert km/hr to m/s, multiply by 5/18: 220 km/hr = 220 * (5/18) m/s = 1100/18 m/s = 550/9 m/s.
– The total distance the trains must cover to cross each other is the sum of their lengths.
– Length of first train = 700 m.
– Length of second train = 400 m.
– Total distance = 700 + 400 = 1100 m.
– Time taken = Total distance / Relative speed.
– Time = 1100 m / (550/9 m/s) = 1100 * (9/550) seconds = (1100/550) * 9 seconds = 2 * 9 seconds = 18 seconds.