A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?

Aptitude Problems on Trains Difficulty: Medium
Choose an option
  • A
    78 km/h
  • B
    79.2 km/h
  • C
    80.4 km/h
  • D
    81.5 km/h

Answer

Correct Answer: 79.2 km/h

Explanation

We are given:

  • Time to cross telegraph post = 8 s
  • Time to cross bridge of 264 m = 20 s

Step 1: Let the train length be L When train crosses post: L / 8 When train crosses bridge: (L + 264) / 20

Step 2: Equating both speeds L / 8 = (L + 264) / 20 20L = 8L + 2112 12L = 2112 ⇒ L = 176 m

Step 3: Calculate speed Speed = 176 / 8 = 22 m/s Convert to km/h: 22 × (18 / 5) = 79.2 km/h

Answer: The speed of the train is 79.2 km/h

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