A train crosses a platform 100 m long in 60 seconds at a speed of 45 kmph.The time taken by the train to cross an electric pole is
a)8 sec b)52 sec c)1 minute d)data inadequate

• Answer is b) 52 sec.
  
  let the length of the train be x m.
  and that of platform is 100m.
  
  :., Total distance covered = (x+100)m
  Speed of the train= 45 km/hr. = 45*5/18 m/s = 12.5 m/s
  
  Since it crosses the platform in 60 sec.
  So, (x+100)/12.5=60
  or, x=60*12.5-100=650m
  
  It will cross an electric pole in 650m/12.5m/s=52sec.
• 11 years agoHelpfull: Yes(2) No(0)