A cow standing on a bridge, 5 m away from the center of the bridge.A train was coming towards the bridge from the end nearest to the cow, seeing this the cow run towards the train and manage to escape when the train was 2m away from the end of the bridge if it had run in the opposite direction it would have been hit by the train 2 m before the end of the bridge. What is the length of the bridge (in m) if speed of train is 4 times the speed of cow ??

let say "x" is the distance of train from the nearest end,
and "Y" be the half length of the bridge.
and "V" velocity of cow,
now (x-2)/4V = (Y-5)/V && (X+2Y-2)/4V = (5+Y-2)/V ;;
solve the above equation to get y = 16m

so, length of the bridge is 32m.
10 years agoHelpfull: Yes(12) No(0)
let speed of cow is x m/s then speed of train will be 4x m/s.
let the distance of train from the nearest end is y mtr.
ans length of bridge 2s mtr.

now when cow run towards the train, time taken will be
(s-5)/x= (y-2)/4x
when cow run opposite to train,
(5+s-2)/x=(y+2s-2)/4x
solving these two equations we get 2s=32 i.e. the length of bridge.
10 years agoHelpfull: Yes(4) No(0)
answer is 16 because if train move 4m then cow run 1m & it is already 5m away from
centre of bridge so length of bridge is (5+2+1)*2 = 16
10 years agoHelpfull: Yes(0) No(7)
@ sandeep. Kumar
train moves 2m so cow moves 1/2m
so length is (2+ 1/2 + 5)*2 = 15
10 years agoHelpfull: Yes(0) No(6)
let length of the bridge is 2l and train is x meters away from the bridge
given speed of cow =y then speed of train=4y

1st case:
(l-3)/y=(x-2)/4y then
x-4l= -10------------->(1)
2nd case:
(l+5-2)/y=(x+2l-2)/4y then
x-2l=14-------------->(2)
solving eq.1 and eq.2
we get
length of bridge=24 meters
8 years agoHelpfull: Yes(0) No(0)

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