Problems on Trains

Ladakh Police Sub-Inspector · Mathematics · 20 practice questions with answers and explanations: 2 Easy, 18 Medium, 0 Hard.

Sample questions

Sample Easy question 1

A 150 m long train running at 54 km/h passes a signal post. How many seconds does it take?

  1. 10
  2. 5
  3. 15
  4. 8
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Answer: A. 54 km/h = 15 m/s. Time = 150 ÷ 15 = 10 seconds.

Sample Easy question 2

A train 200 m long runs at 20 m/s. How long does it take to pass a pole?

  1. 40
  2. 10
  3. 5
  4. 20
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Answer: B. Time = length ÷ speed = 200 ÷ 20 = 10 seconds.

Sample Medium question 3

A train crosses a pole in 20 seconds and a 150 m bridge in 25 seconds. Find its speed in km/h.

  1. 108
  2. 90
  3. 120
  4. 72
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Answer: A. Train length L = 20v and L + 150 = 25v, so 5v = 150, v = 30 m/s = 30 × 18/5 = 108 km/h.

Sample Medium question 4

A passenger counts 21 telegraph posts in one minute. If the posts are 50 m apart, find the speed of the train in km/h.

  1. 60
  2. 63
  3. 72
  4. 50
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Answer: A. 20 gaps × 50 m = 1,000 m in 60 s = 50/3 m/s = 60 km/h. (21 posts make 20 gaps.)

Sample Medium question 5

Two trains, 140 m and 160 m long, run in opposite directions and cross each other in 12 seconds. If one runs at 36 km/h, find the speed of the other.

  1. 54
  2. 45
  3. 72
  4. 60
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Answer: A. Relative speed = 300 ÷ 12 = 25 m/s = 90 km/h. Other train = 90 − 36 = 54 km/h.

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