Two trains are moving in opposite directions at 60 km-hr and 90 km-hr. Their lengths are 1.10 km and 0.9 km respectively. What is the time taken by the slower train to cross the faster train in seconds?
Two trains are moving in opposite directions at 60 km-hr and 90 km-hr. Their lengths are 1.10 km and 0.9 km respectively. What is the time taken by the slower train to cross the faster train in seconds?
Explanation
Speed of the two trains: 60 km/hr and 90 km/hr
If train cross each other, then effective speed = 60 + 90 = 150 km/hr
Length of first train = 1.10 km or 1100 m
Length of second train = 0.9 km or = 900 m
formula
Speed = Distance/Time
⇒ 150 × (5/18) = 2000/Time
⇒ 125/3 = 2000/Time
⇒ Time = 2000 × (3/125)
∴ Time = 48 seconds.
Relative speed = 60 + 90 = 150 km/hr. = 150 x 5/18 = 125/3 m/sec. Distance covered = 1.10 + 0.9 = 2 km = 2000 m. Required time = 2000 x 3/125 = 48 sec.