A train passes a pole in 20 sec and a 300 m long station in 50 sec. Find the length of train.
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Solution
Let the length of train be x meters and its speed be y m/sec.
Then, = 20 ⇒ y =
Now, as in both the cases speed is equal;
so,
Two trains are running in opposite directions with the same speed. If the length of each train is 120 meters and they cross each other in 12 seconds, then the speed of each train (in km/hr) is
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Solution
Let the speed of each train be x m/sec.
Then, relative speed of the two trains = 2x m/sec.
So, 2x = (120 + 120) / 12 ⇒ 2x = 20 ⇔ x = 10.
∴ Speed of each train = 10 m / sec = km/hr = 36 km/hr.
A train crosses a telegraph post in 10 seconds. if the speed of train is 72 km/hr then find the length of train?
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Solution
Speed of train is 72 km/hr
or speed = 72 × (5/18) = 20 m/s
Length of train = 20 × 10 = 200 meter
A 240 meter long train passes a platform in 45 sec while it passes a signal board in 16 sec. What is the length of the platform?
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Solution
From the information given:
Speed of the train = m/sec = 15 m/sec
Let length of the platform be x meters.
Then ,
Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 meters, in what time (in seconds) will they cross each other travelling in opposite direction?
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Solution
Speed of the first train = m/sec = 12 m/sec.
speed of the second train = m/sec = 8 m/sec.
Relative speed = (12+8) = m/sec = 20 m/sec.
∴ Required time = (120+120)/20 sec = 12 sec.
A man sitting in a train which is traveling at 50 kmph observes that a goods train, traveling in opposite direction, takes 9 seconds to pass him. If the goods train is 280 m long, find its speed ?
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Solution
Relative speed =
Speed of goods train = (112 – 50) kmph = 62 kmph.
A train passes a platform in 40 sec and a woman standing on the platform in 30 sec. If the speed of the train is 108 km/hr, what is the length of the platform ?
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Solution
Speed of the train = = 30 m/sec.
Length of the train = Speed of train × Time taken = (30×30) m = 900 m.
Let the length of the platform be x meters.
Then,
Two trains travel in opposite direction at 36 kmph and 45 kmph and a man sitting in slower train passes the faster train in 8 seconds. Then length of the faster train is:
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Solution
Relative Speed = (36 + 45) km/hr =
Length of train = m =180 m.
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
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Solution
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then length of the first train = 27x meters,
And length of the second train = 17y meters.
=> 27x + 17y = 23 (x + y)
=> 27x + 17y = 23x + 23y
4x = 6y
x : y = 3: 2
A train passes a station 120 m long in 60 sec. at a speed of 72 km/hr. the time taken by the train to pass an electric pole is:
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Solution
given that:
Speed of the train = m / sec = 20 m/sec.
Let the length of the train be x meters.
Then, = 60 ⇒ x + 120 = 1200 ⇒ x = 1080.
So, time taken by the train to pass an electric pole = sec = 54 sec.