Speed, Time and Distance
 A train, 200 metre long, is running at a speed of 54 km/hr. The time in seconds that will be taken by train to cross a 175 metre long bridge is :

 12.5
 20
 25
 10

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Speed of train = 54 kmph
= 54 × 5 m/sec. 18
= 15 m/sec.∴ Required time = Length of train and bridge Speed of train = 200 + 175 seconds 15 = 375 seconds 15
= 25 secondsCorrect Option: C
Speed of train = 54 kmph
= 54 × 5 m/sec. 18
= 15 m/sec.∴ Required time = Length of train and bridge Speed of train = 200 + 175 seconds 15 = 375 seconds 15
= 25 seconds
 A train, 500 metre long, running at a uniform speed, passes a station in 35 seconds. If the length of the platform is 221 metre, the speed of the train in km/hr is


72 1 35  74.16
 24.76
 78.54


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Speed of train = Length of platform and train Time taken in crossing = 221 + 500 metre/second 35 = 721 metre/second 35 = 721 × 18 kmph 35 × 5
= 74.16 kmphCorrect Option: B
Speed of train = Length of platform and train Time taken in crossing = 221 + 500 metre/second 35 = 721 metre/second 35 = 721 × 18 kmph 35 × 5
= 74.16 kmph
 The lengths of a train and that of a platform are equal. If with a speed of 90 km/hr the train
crosses the platform in one minute, then the length of the train (in metres) is

 500
 600
 750
 900

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Let, length of train = length of platform = x metre
Speed of train = 90 kmph= 90 × 5 m/sec. 18
= 25 m/sec.∴ Speed of train = Length of platform and train Time taken in crossing ⇒ 25 = 2x ⇒ 2x = 25 × 60 60 ⇒ x = 25 × 60 = 750 metre 2 Correct Option: C
Let, length of train = length of platform = x metre
Speed of train = 90 kmph= 90 × 5 m/sec. 18
= 25 m/sec.∴ Speed of train = Length of platform and train Time taken in crossing ⇒ 25 = 2x ⇒ 2x = 25 × 60 60 ⇒ x = 25 × 60 = 750 metre 2
 A moving train passes a platform 50 metre long in 14 seconds and a lamp post in 10 seconds. The speed of the train (in km/h) is :

 24
 36
 40
 45

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Let the length of train be x metre.
When a train crosses a platform, distance covered by it = length of train and platform.∴ Speed of train = x + 50 = x 14 10 ⇒ x + 50 = x 7 5
⇒ 7x = 5x + 250
⇒ 7x – 5x = 250⇒ 2x = 250 ⇒ x = 250 = 125 metre 2 ∴ Speed of train = x 10 = 125 m./sec. 10 = 125 × 18 kmph 10 5
= 45 kmphCorrect Option: D
Let the length of train be x metre.
When a train crosses a platform, distance covered by it = length of train and platform.∴ Speed of train = x + 50 = x 14 10 ⇒ x + 50 = x 7 5
⇒ 7x = 5x + 250
⇒ 7x – 5x = 250⇒ 2x = 250 ⇒ x = 250 = 125 metre 2 ∴ Speed of train = x 10 = 125 m./sec. 10 = 125 × 18 kmph 10 5
= 45 kmph
 A train 150 metre long takes 20 seconds to cross a platform 450 metre long. The speed of the train in, km per hour, is :

 108
 100
 106
 104

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Speed of train = length of platform and train Time taken in crossing = 450 + 150 m/sec. 20 = 600 m/sec. 20 = 30 × 18 kmph 5
= 108 kmph.Correct Option: A
Speed of train = length of platform and train Time taken in crossing = 450 + 150 m/sec. 20 = 600 m/sec. 20 = 30 × 18 kmph 5
= 108 kmph.