Problems on Trains
- 1. A train 540 m long is running with a speed of 72 km/hr. In what time it pass a tunnel 160 m long?
Options- A. 40 sec
- B. 30 sec
- C. 35 sec
- D. 42 sec Discuss
Correct Answer: 35 sec
Explanation:
? Speed of the train = 72 km/hr = 72 x (5/18) = 20 m/sec.
Sum of the length of the train and tunnel = 540 + 160 = 700 metres.
? Required time taken to pass the tunnel = Time taken to cover 700 metres at 20 m/sec.
= 700/20
= 35 sec.
- 2. A train 200 m long is running with a speed of 72 km/hr. In what time will it pass a platform 160 m long?
Options- A. 18 sec
- B. 21 sec
- C. 15 sec
- D. 20 sec Discuss
Correct Answer: 18 sec
Explanation:
Distance covered = 200 + 160 = 360.
Speed of train = 72 km = 72 x (5/18) = 20 sec.
Time = 360 / 20 = 18 sec.
- 3. A train 150 m long passes a telegraphs post in 12 seconds. Find in what time, it will pass a bridge 250 m long?
Options- A. 32 sec
- B. 36 sec
- C. 25 sec
- D. 24 sec Discuss
Correct Answer: 32 sec
Explanation:
? Speed of the train = 150/12 m/sec.
Required time taken to cross the bridge = [(150 + 250) x (12/150)] = 32 sec.
- 4. A train 280 m long is moving at a speed of 60 km/hr. The time taken by the train to cross a platform 220 m long is?
Options- A. 20 sec
- B. 25 sec
- C. 30 sec
- D. 35 sec Discuss
Correct Answer: 30 sec
Explanation:
Distance covered = 220 + 280 = 500 = 0.5 km
Speed = 60 kmph.
Time taken = 0.5 / 60 hr = (0.5 x 60 x 60)/60 sec
= 30 sec
- 5. A train 700 m long is running at the speed of 72 km/hr. If it cross a tunnel in 1 minute, then the length of the tunnel?
Options- A. 700 m
- B. 600 m
- C. 550 m
- D. 500 m Discuss
Correct Answer: 500 m
Explanation:
length of tunnel + length of train = distances covered by train in 1 min
? length of tunnel + 700 = 72/60 km = 1.2 km = 1200 m
? length of tunnel = 1200 - 700 = 500 m
- 6. A train with 90 km/hr crosses a bridge in 36 seconds. Another train 100 m shorter crosses the same bridge at 45 km/hr. Find the time taken by the second train to cross the bridge?
Options- A. 64 sec
- B. 60 sec
- C. 72 sec
- D. 1 hr Discuss
Correct Answer: 64 sec
Explanation:
Speed of the first train = 90 km/hr = 90 x (5/18) m/sec. = 25 m/sec
Let the length of the train and bridge be L metre.
? L = 25 x 36 = 900 m.....(1)
Again Speed of the second train = 45 km/hr = 45 x (5/18) = 25/2 m/sec.
Now, putting the value from eqn. (1) we have
Time taken = (900 - 100) x 2/25 = 800 x 2/25 = 64 sec
- 7. Two trains 132 metres and 108 metres in length are running towards each other on parallel lines. One at the rate of 32 km/hr and another at 40 km/hr. In what time will they be clear of each other from the moment they meet?
Options- A. 12 sec
- B. 9 sec
- C. 15 sec
- D. Data inadequate Discuss
Correct Answer: 12 sec
Explanation:
Relative speed of the train = (32 + 40) = 72 km/hr = 72 x 5/18 = 20 m/sec.
Sum of length of the train = 132 + 108 = 240 m
time taken by the trains in passing each other = 240/20 = 12 sec .
- 8. A train 700 m long is running at the speed of 72 km per hour. If it crosses a tunnel in 1 minute, then the length of the tunnel is?
Options- A. 500 m
- B. 550 m
- C. 600 m
- D. 700 m Discuss
Correct Answer: 500 m
Explanation:
Speed of the train = 72 x (5/18) = 20 m/sec
Let the length of tunnel = L meters
Then, (700 + L )/ 60 = 20
? 700 + L = 1200
? L = 500 meters
- 9. A trains 100 meters long, running at 36 kmph takes 25 second to pass a bridge. The length of the bridge is?
Options- A. 150 meter
- B. 144 meter
- C. 90 meter
- D. 540 meter Discuss
Correct Answer: 150 meter
Explanation:
Speed = 36 x (5/18) = 10 m/sec
Let the length of the bridge = L m
Distance covered = (100 + L) m
Time taken = 25 sec
? (100 + L ) / 25 = 10 m/sec
? 100 + L = 250
? L = 150 meter
- 10. A train travelling at 48 km/h completely crosses an another train having half length of first train and travelling in opposite directions at 42 km/h in 12 s. It also passes a railways platform in 45 s . The length of the platform is?
Options- A. 400 m
- B. 450 m
- C. 560 m
- D. 600 m Discuss
Correct Answer: 400 m
Explanation:
Let the length of the first train be x m.
Then, the length of second train is (x/2) m
? Relative speed = (48 + 42) km/h = (90 x 5/18) m/s = 25 m/s
According to the question. (x + x/2) / 25 = 12
? 3x/2 = 300
? x = 200 m
? Length of first train = 200 m
Let the length of platform be y m .
Speed of the first train = (48 x 5/18) m/s = 40/3 m/s
Time = Distance / Speed
? (200 + y) x 3/40 = 45
? 600 + 3y = 1800
? y = 400 m
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