A train crosses a platform 100 meters long in 60 seconds at a speed of 45 km…
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A train crosses a platform 100 meters long in 60 seconds at a speed of 45 km per hour. The time taken by the train to cross an electric pole is:
- A.
18 seconds
- B.
1 minute
- C.
52 seconds
- D.
30 seconds
Attempted by 21 students.
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Correct answer: C
Answer: 52 seconds
Let L be the length of the train (in meters).
Speed = 45 km/h = 45 × (5/18) = 12.5 m/s.
Time to cross the 100 m platform = 60 s, so (L + 100)/12.5 = 60.
Therefore L + 100 = 60 × 12.5 = 750 ⇒ L = 750 − 100 = 650 m.
Time to cross an electric pole (distance = train length) = L/12.5 = 650/12.5 = 52 seconds.
Hence the train takes 52 seconds to cross the pole.