At 12.00 hours, J starts to walk from his house at 6 kmph. At 13.30, P follows him from J's house on his bicycle at 8 kmph. When will J be 3 km behind P?

• let t be the time taken
  8t-(6(t+1.5))=3
  t=6
  then 13.30+6=19.30 so j will be 3 km behind p at 19.30
  
• 10 years agoHelpfull: Yes(13) No(3)
• at 13.30,j will be 9 km from his house,p is starting now
  at 14.30,j =9+6=15km, p=8km
  at 15.30,j=21km,p=16km
  at 16.30,j=27km,p=24km
  at 17.30,j=33km,p=32km
  at 18.30,j=39km,p=40km
  at 19.30,j=45km,p=48km
  thus at 19.30 ,j is behind p from 3 km
  
  
• 10 years agoHelpfull: Yes(8) No(0)
• j in 1.5 hr cover the distance=1.5*6=9 km
  
  p follow J with his bicycle with the speed=8km/h
  
  J is 3 km behind when P is 3 km ahead of him. ie., P has to cover 12 km so he takes= (9+3)/8-6= 6 hr
  
  total time=13:30 + 6 =19:30 hr Ans
• 10 years agoHelpfull: Yes(4) No(0)
• ans 19: 30
  
• 10 years agoHelpfull: Yes(0) No(0)