Question
A train A of length 200 m is moving at 72 km/h. It meets
another train B coming from the opposite direction at 54 km/h. If the two trains completely cross each other in 16 seconds, what is the length of train B (in metres)?Solution
ATQ, Convert speeds to m/s: 72 km/h = 72 × 1000/3600 = 20 m/s 54 km/h = 15 m/s Relative speed (opposite directions) = 20 + 15 = 35 m/s. Time to cross = 16 s ⇒ total distance covered = 35 × 16 = 560 m. Total distance = length(A) + length(B) = 200 + L_B = 560 L_B = 560 − 200 = 360 m.
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