A 270 metres long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kmph in 9 seconds. What is the length of the other train?

• Ans is 230 m
  speed = (120 + 80)km/h (because direction is opposite hence relative velocity is added)= 500/9 m/s
  time= 9sec
  let the lenght of second train is x
  total distance covered= 270 + x
  therefore, D= speed*time
  thus 270 + x = 500/9 * 9
  x= 500-270=230 m
• 13 years agoHelpfull: Yes(23) No(2)
• atfirst we have to find out the relative speed
  relative speed=(120+80)=200kmph
  now we have to convert it in m/s
  (200*5/18)=55.55m/s
  let the length of the train is x
  So in 9 sec (x+270)m must b crossed
  (x+270)/9=55.55
  so x=230
  
• 13 years agoHelpfull: Yes(10) No(1)
• "If two trains lengths are x m and y m and moving in the opposite directions at u m/s and v m/s, then the time taken by the trains to cross each other=(x+y)/(u+v) seconds."
  According to the problem, x=270m, y=?m,u=120kmph=120*5/18=300/9mps and v=80kmph=200/9mps.
  Now, 9=(270+y)/(300/9+200/9)==>y=230m,
  Therefore length of the other train=230m
• 13 years agoHelpfull: Yes(4) No(0)
• ANS IS:230
  A TRAIN LENGTH =270
  SPEED=120KMP/H
  B TRAIN LENGTH=X
  SPEED=80KMP/H
  TIME=9 SECOND
  LENGTH=SPEED*TIME
  =120+80=200KMP/H
  =200*5/18=1000/18
  LENGTH=1000/18*9=500
  B TRAIN LENGTH =500-270=230
• 9 years agoHelpfull: Yes(4) No(0)
• As Two Trains Ar Comming Fron Opposite Side,So Their Speed Is (120+80)=200kmph
  converting The kmph into metre/secont is (200*1000)3600=(2000/36)
  Let The Length Of Other Train Is x metres.
  Total Length Of Two Trains Is (x+270)metres.
  1st Train Cross The 2nd Train in 9 Second.
  In 1 Second,It Will Travel (x+270)/9 metres.
  It Is The Relative Speed Of The Two Trains.
  So,((270+x)/9))=2000/36
  Solving The Equation We Get x=230 metres.
  So,Length Of The Other Train Is 230 Metres.
• 13 years agoHelpfull: Yes(0) No(0)
• speed=distance/time
  relative speed=120+80=200kmph
  converting kmph into mpsec by multiplying it by 5/18
  so 200*(5/18)=500/9
  500/9=(270+x)/9
  x=230.
• 13 years agoHelpfull: Yes(0) No(0)
• speed = (120 + 80)km/h (because direction is opposite hence relative velocity is added)= 500/9 m/s
  time= 9sec
  let the lenght of second train is x
  total distance covered= 270 + x
  therefore, D= speed*time
  thus 270 + x = 500/9 * 9
  x= 500-270=230 m
• 9 years agoHelpfull: Yes(0) No(0)
• 200*5/18 = 500/9 and then 9*500/9 = 500 so length of both train is 500 metre, then if one train length is 270 given and other is 230 , so 230 is the right answer
• 9 years agoHelpfull: Yes(0) No(0)
• speed=distance/time
  relative speed=120+80=200kmph
  
  Now, converting km/h into m/s by multiplying 5/18
  200*(5/18)=500/9
  Recall, s=d/t
  500/9=(270+x)/9
  x=230.
• 8 years agoHelpfull: Yes(0) No(0)
• Use formula time = Length of the two trains / relative speed
  so the answer is 230m
  
  
• 8 years agoHelpfull: Yes(0) No(0)