Multiple choice

Passage

Directions: The question is followed by two statements I and II. You have to determine whether the data given in the statements is sufficient for answering the question. You should use the data and your knowledge of Mathematics to choose the best possible answer.

Train Y, which has a length of 450 m and is running at 72 kmph, will take how much time to cross train Z, which is 550 m long and is running at a certain speed in the opposite direction? I. Train Z is faster than Train Y. It takes 100 seconds for both the trains to get apart from each other moving in the same direction. II. Train Z can cover 288 km in 2 hours and 40 minutes.

  1. The question can be answered by using statement I alone but cannot be answered by using the other statement alone.

  2. The question can be answered by using statement II alone but cannot be answered by using the other statement alone.

  3. The question can be answered by using either of the statements alone.

  4. The question can be answered by using both of the statements together, but cannot be answered by using either of the statements alone.

  5. The question cannot be answered even by using both the statements together.
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B Correct answer
AI explanation

To find the required time we must know the speed of train Z, and statement II provides this by yielding a speed of 288 km divided by 2.66 hours, which equals 108 kmph. Using this speed, the relative speed for trains moving in opposite directions is 72 kmph plus 108 kmph, or 180 kmph, which converts to 50 m/s. The time to cross each other is the total length of 1000 m divided by this relative speed, giving 20 seconds. Statement I only provides relative speed for the same direction, which is insufficient to find the opposite direction crossing time, so the question can be answered by using statement II alone but cannot be answered by using the other statement alone.

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