A man goes upstream in a certain place in 3 hours. Another man covers the same distance in downstream in 5 hours. The speed of river is 10km/hr. The speed difference between them?

• i think ans is 20km/hr
• 11 years agoHelpfull: Yes(5) No(3)
• Answer is 40km/h.
  
  let y is the speed of the stream, where y=10km/hr(given)
  
  let a is the time taken by first man to cover some distance, where a=3 hours(given)
  
  let b is the time taken by second person to cover same distance as first, where b=5 hours(given)
  
  According to the formula, y(a+b)/(b-a) = 10(3+5)/5-3 = 40km/hr
  
  their is no need to subtract 10 from 40 as its the speed of the stream which automatically adds to the speed of the person.
  
  therefore answer is 40km/hr.
• 10 years agoHelpfull: Yes(3) No(1)
• answer is 30
  
  (x+10)*3 = (x-10)*5
  gives x=40
  40 - 10 gives the difference of 10 kmph
  formula used:
  upstream= (speed of boat -speed of stream)
  downstream=(speed of boat +speed of stream)
  hoe its clear now!
• 11 years agoHelpfull: Yes(2) No(11)