Sona travels 600 km to his house partly by train and
partly by car. He takes 8 hours if he travels 120 km
by train and the rest by car. He takes 20 minutes
more if he travels 200 km by train and the rest by
car. Find the speed of the train in km/h.
(1) 45 (2) 60 (3) 75
(4) 80 (5) None of these

• let x=speed of train
  let y=speed of car
  travel time=distance/speed
  ..
  120/x+480/y=8
  200/x+400/y=8+1/3=25/3
  ..
  let u=1/x
  let v=1/y
  ..
  120u+480v=8
  200u+400v=25/3
  ..
  120u+480v=8
  
  
  600u+1200v=25
  ..
  600u+2400v=40 (multi. by 5)
  600u+1200v=25
  subtract
  1200v=15
  v=15/1200
  y=1/v=1200/15=80
  ..
  120u=8-480v=8-(480*15/1200)=8-6=2
  u=2/120=1/x
  x=120/2=60
  ..
  ans:
  speed of train=60 km/hr
  speed of car=80 km/hr
• 9 years agoHelpfull: Yes(4) No(2)
• speed of train 150km/hr and speed of car 400 km/hr
• 9 years agoHelpfull: Yes(0) No(4)