Speed, Time and Distance
 A train passes two bridges of lengths 500 m and 250 m in 100 seconds and 60 seconds respectively. The length of the train is :

 152 m
 125 m
 250 m
 120 m

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Length of train = x metre (let)
Speed of train
=(Length of train and bridge) Time taken in crossing ⇒ x + 500 = x + 250 100 60 ⇒ x + 500 = x + 250 5 3
⇒ 5x + 1250 = 3x + 1500
⇒ 5x – 3x = 1500 – 1250
⇒ 2x = 250⇒ x = 250 = 125 metre 2 Correct Option: B
Length of train = x metre (let)
Speed of train
=(Length of train and bridge) Time taken in crossing ⇒ x + 500 = x + 250 100 60 ⇒ x + 500 = x + 250 5 3
⇒ 5x + 1250 = 3x + 1500
⇒ 5x – 3x = 1500 – 1250
⇒ 2x = 250⇒ x = 250 = 125 metre 2
 A 200 metre long train is running at a speed of 72 km/hr. How long will it take to cross 800metre long bridge ?

 50 seconds
 40 seconds
 60 seconds
 30 seconds

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Speed of train = 72 kmph
= 72 × 5 m/sec. 18
= 20 m/sec.Required time
=Length of train and bridge Speed of train = (200 + 800) 20 = 1000 = 50 seconds 20 Correct Option: A
Speed of train = 72 kmph
= 72 × 5 m/sec. 18
= 20 m/sec.Required time
=Length of train and bridge Speed of train = (200 + 800) 20 = 1000 = 50 seconds 20
 If a man running at 15 kmph crosses a bridge in 5 minutes, the length of the bridge is

 1000 metres
 500 metres
 750 metres
 1250 metres

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Time = 5 minutes
= 1 hour 12
∴ Length of bridge = Speed × Time= 15 × 1 = 5 km. 12 4 = 5 × 1000 metre 4
= 1250 metreCorrect Option: D
Time = 5 minutes
= 1 hour 12
∴ Length of bridge = Speed × Time= 15 × 1 = 5 km. 12 4 = 5 × 1000 metre 4
= 1250 metre
 How many seconds will a train 120 metre long running at the rate of 36 km/hr take to cross a bridge of 360 metres in length ?

 48 sec
 40 sec
 46 sec
 36 sec

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Speed of train = 36 kmph
= 36 × 5 m/sec. 18
= 10 m/secRequired time
=Length of train and bridge Speed of train = 120 + 360 = 480 = 48 seconds 10 10 Correct Option: A
Speed of train = 36 kmph
= 36 × 5 m/sec. 18
= 10 m/secRequired time
=Length of train and bridge Speed of train = 120 + 360 = 480 = 48 seconds 10 10
 A train 50 metre long passes a platform 100 metre long in 10 seconds. The speed of the train in km/hr is

 10
 54
 15
 100

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Speed of train = Length of platform and train Time taken to crossing = 100 + 50 metre/second 10
= 15 metre/second= 15 × 18 kmph 5
= 54 kmphCorrect Option: B
Speed of train = Length of platform and train Time taken to crossing = 100 + 50 metre/second 10
= 15 metre/second= 15 × 18 kmph 5
= 54 kmph