Question 50
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A cow was standing on a bridge, 5m away from the middle of the bridge. A train was coming towards the bridge from the ends nearest to the cow. Seeing this cow ran towards the the train and managed to escape when the train was 2m away from bridge. If it had run in the opposite direction, it would hit by the train 2m before the end of the bridge. What is the length of the bridge in meters assuming the speed of the train is 4 times that of cow ?
- A 22 mts
- B 28 mts
- C 32 mts Correct
- D 34 mts
Correct Answer: Option C
Let 'b' be the Length of bridge from cow to the near end of the bridge and 'a' be the distance of the train from the bridge.
'x' be speed of cow => '4x' speed of train
Then the total length of the bridge 2b + 10.
( a - 2 )/4x = b/x
=> a - 2 = 4b........(1)
Now if it had run in opposite direction
( a + 2b + 10 - 2 )/4x = ( b + 10 - 2 )/x
=> a - 2b = 24......(2)
Solving (1) and (2)
b = 11
Therefore length of the bridge is 2 x 11 + 10 = 32mts.
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