A person is standing on a railway bridge 70m. Long. He finds that a traincrosses the bridge in 6 secs. but himself in 4 secs. Find the length of the trainand its speed in km/hr.

• let length of train=x
  then,train covers x metres in 4 sec and(x+70)m in 6sec
  so,x/4=(x+70)/6
  x=140m.
  speed lf train=140/4=35m/s
• 12 years agoHelpfull: Yes(28) No(1)
• let the length of train be x mt
  so the distance become (X+70) mt
  now X/4=(x+70)/6
  Ans X=140mt length of train
  
  now we have find the speed of train
  speed= (x+70)/6
  speed =(140+70)/6
  speed = 35mt/sec
  now convert into kmph
  =35*(18/5)
  speed=126kmph Ans....
  
  
• 12 years agoHelpfull: Yes(12) No(2)
• time taken to cros bridge= len of train + len of bridge/speed
  s=70+len of train/6
  another equ for man s= len of train /4
  compare two equ
• 12 years agoHelpfull: Yes(10) No(1)
• ans is 140
  
• 12 years agoHelpfull: Yes(7) No(1)
• Let, speed of train be x m/s.
  Length of train = 4x meter.
  
  according to question,
  (70+4x)/x=6
  =>x=35 m/s
  so, 35*18/5=126 Km/h is the answer.
• 12 years agoHelpfull: Yes(7) No(6)
• let train length=x and speed =s
  so accordind to ques
  s=t/4.......(1)
  and
  s=(70+t)/6....(2)
  on solving
  x=140m..ans
  and speed s=140/4 ie 35 m/s
  which is equal to 35*18/5 =126 kmph
• 12 years agoHelpfull: Yes(2) No(0)
• can you explain why 140?
• 12 years agoHelpfull: Yes(1) No(0)
• length of train=x
  then,x%4=(x+70)%6
  x=140(
  speed of the train=120%4=30m/s
• 12 years agoHelpfull: Yes(0) No(4)