Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one?
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Solution
Relative speed = (45 + 30) km/hr = m/sec = m/sec.
Distance covered = (500+500) m = 1000 m.
Required time = Sec.= 48 sec.
A train 200 m long passes a man, running at 15 kmph in the same direction in which the train is going, in 5 seconds. The speed of the train is?
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Solution
Speed of the train relative to man = m/sec = 40 m/sec.
= 40 x (18/5)km/hr = 144 km/hr.
Let the speed of the train be x kmph. Then relative speed = (x-15) kmph
∴ x – 15 = 144 or x = 159 kmph.
Two trains are moving in opposite directions @ 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is:
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Solution
Relative speed = (60 + 90) km/hr
= m/sec = m/sec.
Distance covered = (1.10+0.9) km = 2 km = 2000 m.
Required time = sec = 48 sec.
Two trains 140 m and 160 m long run tat the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is
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Solution
Relative speed = (60 + 40) km/hr = m/sec = m/sec.
Distance covered in crossing each other = (140+160)m = 300 m
Required time = sec = sec = 10.8 sec.
A train 108 m long is moving at a speed of 50 km/hr . It crosses a train 112 m long coming from opposite direction in 6 seconds. What is the speed of the second train?
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Solution
Total distance = 108 + 112 = 220 m
Time = 6 s
Relative speed = distance/time = 220/6 m/s = 110/3 m/s
= (110/3) × (18/5) km/hr = 132 km/hr
⇒ 50 + speed of second train = 132 km/hr
⇒ Speed of second train = 132-50 = 82 km/hr
How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr ?
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Solution
Speed of train relative to man = (63 – 3) km/hr = 60 km/hr
= m/sec = m/sec.
∴ Time taken to pass the man = sec = 30 sec.
A train speed past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:
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Solution
Let the length of the train be x meters and its speed be y m/sec.
They, = 15 ⇒y = .
∴ = ⇔x = 150 m.
A train of length 800 meter takes 4 minutes to cross 2400 meter bridge. find the speed of train (in meter/second)?
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Solution
Total distance travelled = 800 + 2400 = 3200 meter
Time = 4 minutes = 240 seconds
Speed = distance/time = = 13.33 meter/second
A train, 160 meter long cross 80 meter long bridge in 30 second. What time will it take to pass a post?
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Solution
Speed of train = = 8 m/s
Time taken by it to pass by a post = = 20 seconds
If the two trains moving in opposite directions at the speed of 80 kmph and x kmph reach their destinations in 72 and 32 minutes respectively after they pass each other. Find x ?
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Solution
Ratio of their speeds will be =
OR 2 : 3
So speed of second train is = 120 km/hr