Two trains A and B cross each other in 12 seconds when they move towards each…
2018
Two trains A and B cross each other in 12 seconds when they move towards each other. Speed of train A and train B is 81 km/hr and 54 km/hr respectively. Length of train A is 150 metre more than length of train B.
→ Which of the following can be obtained from the above given information.
(i) Time taken by train B to cross a man moving in same direction as of train B.
(ii) Time taken by train A to cross a platform of half of its length.
(iii) Length of train A.
(iv) Speed of another train C whose length is equal to average of length of train A and B.
- A.
(i) and (iii)
- B.
(i), (ii) and (iii)
- C.
(ii) and (iii)
- D.
All (i), (ii), (iii) and (iv)
- E.
(i) and (iv)
Attempted by 5 students.
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Correct answer: C
The relative speed of the two trains is 81 + 54 = 135 km/h = 37.5 m/s.
They cross each other in 12 seconds, so the sum of their lengths is 37.5 x 12 = 450 m. Since train A is 150 m longer than train B, train A is 300 m and train B is 150 m.
Thus statement (iii), length of train A, can be found. Statement (ii) can also be found because train A's speed and platform length are known. Statements (i) and (iv) require extra missing information.