A train travelling at 48 kmph crosses another train, having half its length and travelling in opposite direction at 42 kmph, in 12 sec. It also covers a bridge in 45 sec. Find the length of the bridge ?
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Let the length of the train be x cm.
According to the question, length of second train is x/2 cm.
According to the question, total speed of both trains is 48+42 kmph = 90 kmph
90kmph= (90×1000)÷(60×60)m/s = 25 m/s
According to the question:
x+(x/2)=25×12 [distance=speed×time]
=>(2x+x)/2=300
=>3x=600
=>x=200m
Now we know the length of train is 200m.
Let the length of platform be d metres
According to the question:
Distance= length of bridge+ length of train
Therefore, distance= 200m + d m
Now, we use the formulae distance=speed×time
Therefore, (d+200)=48×(5/18)×45
=)d+200=600
=)d=400m
Therefore, length of platform is 400m.
According to the question, length of second train is x/2 cm.
According to the question, total speed of both trains is 48+42 kmph = 90 kmph
90kmph= (90×1000)÷(60×60)m/s = 25 m/s
According to the question:
x+(x/2)=25×12 [distance=speed×time]
=>(2x+x)/2=300
=>3x=600
=>x=200m
Now we know the length of train is 200m.
Let the length of platform be d metres
According to the question:
Distance= length of bridge+ length of train
Therefore, distance= 200m + d m
Now, we use the formulae distance=speed×time
Therefore, (d+200)=48×(5/18)×45
=)d+200=600
=)d=400m
Therefore, length of platform is 400m.
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