Problem on Trains
 A train 110 metres in length travels at 60 km/hr.In what time will it pass a man which is walking against the train at 6 km an hour?

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∵ Relative speed of the train = 60 + 6 = 66 km/hr
= 66 x 5/18 m/sec = 55/3 m/secCorrect Option: B
∵ Relative speed of the train = 60 + 6 = 66 km/hr
= 66 x 5/18 m/sec = 55/3 m/sec
∴ Required time = 110 x (3/55) = 6 sec
 A train 50 m long passes a platform 100 m long in 10 seconds. The speed of the train in m/sec is ?

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Speed of train = distance covered / time.
= (50 + 100) / 10 m/secCorrect Option: D
Speed of train = distance covered / time.
= (50 + 100) / 10
= 15 m/sec.
 A train 110 m long travels at 60 km/hr. How long does it take to cross a platform 240 metres long ?

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Distance covered = 110 + 240 = 350 m
Speed = 60 km/ph = 60 x (5/18) m/s = 50/3 m/sec.Correct Option: A
Distance covered = 110 + 240 = 350 m
Speed = 60 km/ph = 60 x (5/18) m/s = 50/3 m/sec.
Time = distance / speed = 350 x 3 / 50 = 21 sec.
 A train 240 m long passes a bridge 120 m long in 24 sec. Find the speed with which the train in moving ?

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Required speed = (240 + 120) / 24 = 15 m/sec
= 15 x (18/5) km/hr = 54 km/hrCorrect Option: B
Required speed = (240 + 120) / 24 = 15 m/sec
= 15 x (18/5) km/hr = 54 km/hr
 Two trains 70 m and 80 m long respectively, run at the rates of 68 km and 40 km an hour respectively, on parallel rails in opposite directions. How long do they take to pass each other ?

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Total distance = 70 + 80 = 150 m
Relative speed = 68 + 40 = 108 kmph = 108 x (5/18) = 30 m/sCorrect Option: A
Total distance = 70 + 80 = 150 m
Relative speed = 68 + 40 = 108 kmph = 108 x (5/18) = 30 m/s
So time taken = 150 / 30 = 5 seconds.