Multiple choice

What is the speed of a train? I. The train crosses a telephone pole in 30 sec. II. The train crosses a bridge of 200 m. length in 40 sec.

  1. If statement I alone is sufficient but statement II alone is not sufficient.

  2. If statement II alone is sufficient but statement I alone is not sufficient.

  3. If each statement alone (either I or II) is sufficient.

  4. If statement I and II together are not sufficient.

  5. If both statement together are sufficient, but neither statement alone is sufficient.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Statement I gives length/time but not actual length or speed. Statement II gives bridge length and time but not train length. Neither alone is sufficient. Together: length = speed×30, and length+200 = speed×40. Solving gives speed = 20 m/s. Both needed, so E is correct.

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