A man row 12.6 km downstream in 36min. River speed is 1/7th of downstream spd. If he goes A to B upstream and return to point A in 4 hour. Find the distance? ???

• speed of river = y kmph
  speed of boat = x kmph
  downspeed = x+y
  given , y= (x+y)/7
  so x = 6y..... (i)
  speed = dist / time
  x+y = 12.6*60/36 = 21... (ii)
  on solving (i) and (ii)
  y=3, x=18
  total time from A to B and back to A = 4 hours
  let d be distance between A and B
  4 = t1+t2
  4 = d/(x+y) + d/(x-y)
  4 = d/21 + d/15
  d = 35 Km
  
• 9 years agoHelpfull: Yes(0) No(0)