Multiple choice

What is the speed of train X? I. Train X crosses 140 m. long train Y moving in opposite direction in 10 seconds. II. Train X crosses 400 m. long platform in 28 seconds. III. Train X crosses a man standing on the platform in 8 seconds.

  1. I and II

  2. II and III

  3. I and III

  4. Any of two

  5. Can't given the answer included three statement also
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement II gives: Length of train X + 400 = 28 × speed of train X. This alone cannot give the speed. Statement III gives: Length of train X = 8 × speed of train X. From III, speed = Length/8. Substituting in II: Length + 400 = 28 × (Length/8) = 3.5 × Length, so 400 = 2.5 × Length, Length = 160 m, Speed = 160/8 = 20 m/s. Statements II and III together are sufficient. Statement I is not needed as we don't need train Y's details.

Keep practicing — related questions