Multiple choice

The length of train A is twice that of train B and speed of train A is half of that of train B. If train A crosses a man in 4 sec. then find how long will train B take to cross train A if they go in same direction.

  1. 3 second

  2. 4 second

  3. 5 second

  4. 6 second

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let train B have length L and speed V. Then train A has length 2L and speed V/2. Train A crosses man in 4 sec: 2L = (V/2) × 4, so V = L. In same direction, relative speed = V - V/2 = V/2. Time to cross: 3L/(V/2) = 3L/(L/2) = 6 seconds.

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