a train passes two cars moving in the direction at 45km/hr and 50km/hr in 36 sec and 54 sec respectively. What is the length of the train?

• Let us assume::
  the length of train is x km.
  the velocity of the train is v km/h.
  
  Case A:: Car A.
  Velocity is 45km/h.
  Time is 36 secs = 36/3600hr = 0.01 hr.
  Since train crosses the cars, v is greater than velocity of car.
  so the net velocity is (v-45)kmph.
  Distance=speed*time.
  Here the distance covered is nothing but length of train.
  Therefore
  x = (v-45)*0.01 ...............................(1)
  Similarly from car 2:
  x = (v-50)*0.015...............................(2)
  
  Divide and solve for v,from the above equations,
  v=60 kmph.
  put in (1).
  x=(60-45)*0.01
  x=0.15 km
  Hence x = 150 m
  Therefore the length of train is 150 m.
• 6 years agoHelpfull: Yes(1) No(0)
• 1200m
  distance=speed*time
  45*518*36+50*518*54
  1200
  
• 10 years agoHelpfull: Yes(0) No(2)