A man rows to a place 48 km distant and come back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The rate of the stream is:

A. 1 km/hr
B. 1.5 km/hr
C. 2 km/hr
D. 2.5 km/hr

• A. 1 km/hr
  
  If upstream speed is 3x and downstream speed is 4x, then
  
  48/4x + 48/3x = 14
  then x= 2
  
  Hence if speed of boat in still water is B and speed of stream is S, then
  B+S = 8 km/hr
  B-S = 6 Km/hr
  solving it, we get
  
  S= 1 km/hr and B= 7 km/hr
• 12 years agoHelpfull: Yes(9) No(8)
• tforward=4/v+u,toppisite=3/v-u,
  given tf=topp
  here we get v=7u
  now acc. to condition
  48/v+u+48/v-u=14
  put value of v and get u=1km/hr.ans.
  put
• 11 years agoHelpfull: Yes(5) No(0)
• as same time required so 4/x=3/x or inverse is speed so x/4=x/3
  so 48/(x/4)-48/(x/3)=14 we get x=24km
  so down speed=24/3=8km/hr & up speed =24/4=6km/hr
  so let boat speed=B & stream speed=S
  so B+S=8
  & B-S=6
  so we get B=7km/hr & S=1km/hr
• 11 years agoHelpfull: Yes(2) No(1)
• let stream rate u and man's rate v
  4/(v+u)=3/(v-u) or
  v=7u
  now 48/(8u) +48/(6u)=14
  u=1km/hr
• 8 years agoHelpfull: Yes(2) No(0)
• 48/(x+y) +48/(x-y)=14.......(i)
  4/(x+y)=3/(x-y),
  x=7y..........(ii)
  solving this two eq we get x=1kmh
• 8 years agoHelpfull: Yes(1) No(0)