A train with 90 km/h crosses a bridge in 36 seconds. another train 100 metres shorter crosses the same bridge at 45 km/h. what is the time taken by the second train to cross the bridge ?
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Let the distance of bridge be 'x'.
let the length of the first train be 'y'.
Then distance travelled by first train =x+y.
hence (x+y) =90×(5/18)×36
=25×36
=900 metres.
Give length of second train =y-100
length of bridge i same as above
Then total distance travelled by second one= x+(y-100)=45×(5/18)×t
x+y =25/2×t+100
by substituting above equation
900=25/2×t+100
800=25/2×t
t = 1600/25
t= 64 seconds.
let the length of the first train be 'y'.
Then distance travelled by first train =x+y.
hence (x+y) =90×(5/18)×36
=25×36
=900 metres.
Give length of second train =y-100
length of bridge i same as above
Then total distance travelled by second one= x+(y-100)=45×(5/18)×t
x+y =25/2×t+100
by substituting above equation
900=25/2×t+100
800=25/2×t
t = 1600/25
t= 64 seconds.
srinivasvenkat99:
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Answered by
1
Answer:
64s
Step-by-step explanation:
Total length=90*(5/18)*36= 900
Now
New length=900-100=800
Required time for 2nd train= 800/(25/2)= 64s
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