Multiple choice

Directions: In this question, you have to find out which of the following statements is/are sufficient for determining the answer of the given question. What is the speed of the train? I. The train crosses another train in the same direction in 50 seconds. II. The train crosses a tree in 22 seconds. III. The train crosses a platform of length 380 metres in 42 seconds.

  1. Only I and II

  2. Only II and III

  3. Only II and either I or III

  4. Either II or III

  5. All I, II and III
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let L be length of train and V be speed. II: L/V = 22. III: (L+380)/V = 42. From II, L = 22V. Substitute into III: (22V + 380)/V = 42 => 22V + 380 = 42V => 20V = 380 => V = 19 m/s. Statement I is not needed.

AI explanation

Let the speed of the train be v and its length be L. Statement II provides the equation L = 22v. Statement III provides the equation L + 380 = 42v. Substituting 22v for L in the second equation gives 22v + 380 = 42v, which simplifies to 20v = 380, yielding a speed of 19 m/s. Since statement I lacks the lengths or speeds of the other train, it is insufficient. Therefore, only statements II and III are sufficient to determine the answer.

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