Multiple choice

The length of a platform is 1,750 yards, and a train crosses the platform in 47 seconds and a man in 22 seconds. What is the speed at which the train is traveling?

  1. 72 yards per second

  2. 70 yards per second

  3. 68 yards per second

  4. 62 yards per second

  5. 56 yards per second
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let train length be L and speed be S. L + 1750 = 47S and L = 22S. Subtracting gives 1750 = 25S. S = 1750 / 25 = 70 yards per second.

AI explanation

Using the formula speed equals distance divided by time, let the train length be L and its speed be S. Crossing the man in 22 seconds means L equals 22 times S. Crossing the 1750 yard platform in 47 seconds means L plus 1750 equals 47 times S. Substituting 22 times S for L gives 22 times S plus 1750 equals 47 times S, so 25 times S equals 1750. The speed is 1750 divided by 25, which is 70 yards per second.

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