A man in a train notices that he can count 21 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed is the train travelling?
A. 55 km/hr B. 57 km/hr
C. 60 km/hr D. 63 km/hr

• C. 60 km/hr
  
  Distance covered in 1 min = 20*50 = 1000 m = 1km
  Distance covered in 1 hr = 60 km
  so speed = 60 kmph
• 12 years agoHelpfull: Yes(19) No(18)
• R8 Ans= 63 km/hr
• 9 years agoHelpfull: Yes(6) No(2)
• c) 60km/hr
  21 telephn posts....ie 20 spaces btween thm ..therefore dist=20*50=1000
  s=d/t time given 60sec
  after solvng convrt it into km/hr
• 8 years agoHelpfull: Yes(1) No(2)
• It will be 60km/hr
  As distance covered in 1minute = 20*50 = 1000m = 1km
  Distance covered in 1hour= 60km
• 8 years agoHelpfull: Yes(1) No(1)
• Ans: 60 km/hr
  because,
  there is 21 posts he can count in a minute. distance between the posts is 50 metres.
  then the distance covered by train in a minute is 1 km.
  so the speed of the train is 60 km/ hr
• 9 years agoHelpfull: Yes(0) No(1)
• 20*60=1000mtrs per mnt
  so speed of the train is 60kmph
• 8 years agoHelpfull: Yes(0) No(1)
• Time to cross 21 telephone (t) = 1min = 1/60hr
  Distance from 1st telephone post to 21st (d) = (21-1)*50m = 1000m = 1km
  Speed of train (s) = d/t = 1km/(1/60)hr = 60 km/Hr
• 3 years agoHelpfull: Yes(0) No(0)