A speedboat whose speed is 15 kmph in still water goes 30 kmph downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph?

• sorry
  the answer is 5kmph
  solution:-
  Let the speed of the stream be x km/hr. Then,
  
  Speed downstream = (15 + x) km/hr,
  Speed upstream = (15 - x) km/ph
  30/(15+x)+30/(15-x)=4.5
  solve for x
  x=5kmph
  
  
  
  x = 5 km/hr.
• 9 years agoHelpfull: Yes(20) No(3)
• but 30kmph is not the distance
  
• 9 years agoHelpfull: Yes(14) No(5)
• i think its 15 km/hr... bcoz
  ds=boatspeed + streamspeed (let stream speed = x)
  => 30=15 + x
  => x = 15 km / hr
  
• 9 years agoHelpfull: Yes(12) No(7)
• Ans is 5 kmph
  Sorry speed of the strem is 5kmph
  let x is apeed of stream
  30/(15+x)+30/(15-x)=4.5
  solve for x you will get x=5
• 9 years agoHelpfull: Yes(9) No(2)
• let the speed of boat in still water=x kmph
  speed of stream= y kmph
  down stream=ds
  ds=x+y
  y=ds-x=30-15=15kmph
• 9 years agoHelpfull: Yes(4) No(7)
• ans is 5kmph..
  as we know the formula,speed downstream=(speed in still water+speed of stream)
  
  now,let speed of stream be x..
  
  so,by the given formula we get
  
  30=(15+x)..
  
  again in the given question the boat comes back,so 30=(15-x)
  
  Therefore,by the given 2equations,
  
  30/(15+x) + 30/(15-x)=4.5(time given)
  
  solving we see,x=5
  
  
  Hence the speed of the stream is 5kmph..
• 9 years agoHelpfull: Yes(4) No(0)
• ans is 20 km/p
  the speed of water is 20 km per hour
• 9 years agoHelpfull: Yes(2) No(9)
• In this question , it should be "A speedboat whose speed is 15 kmph in still water goes 30 km downstream " and not 30kmph !!!
• 9 years agoHelpfull: Yes(2) No(0)
• hear distance is not 30 km
  
  I think answer is 15 kmph because in downstream boat speed= speed in still water + stream speed
  So, 15 + stream speed = 30 =====.> strem speed = 15 kmph
  
• 9 years agoHelpfull: Yes(1) No(1)
• Let the speed of the stream be x km/hr. Then,
  
  Speed downstream = (15 + x) km/hr,
  
  Speed upstream = (15 - x) km/hr.
  
  30 + 30 = 4 1
  (15 + x) (15 - x) 2
  900 = 9
  225 - x2 2
  9x2 = 225
  
  x2 = 25
  
  x = 5 km/hr.
  
  ****note: 30 km downstream means it goes 30 km.It is distance
• 9 years agoHelpfull: Yes(1) No(3)
• if 30kmph is the combined speed then the answer will be 30-15=15
  but if it is distance 30 km then answer is 5kmph
• 9 years agoHelpfull: Yes(1) No(1)
• the question is given wrong
  A speedboat whose speed is 15 kmph in still water goes 30 km downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph
  that is the exact ques.
  and ans is 5 km.
  A speedboat whose speed is 15 kmph in still water goes 30 kmph downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph
  
• 9 years agoHelpfull: Yes(1) No(1)
• Let the speed of the stream be x km/hr. Then,
  
  Speed downstream = (15 + x) km/hr,
  
  Speed upstream = (15 - x) km/hr.
  
  30 + 30 = 4 1
  (15 + x) (15 - x) 2
  900 = 9
  225 - x2 2
  9x2 = 225
  
  x2 = 25
  
  x = 5 km/hr.
• 7 years agoHelpfull: Yes(1) No(1)
• speed of stream= downstream speed - speed of the boat in still water
  = 30-15=15kmph
• 9 years agoHelpfull: Yes(0) No(1)
• ans 15kmph.
  speed of boat=15 kmph
  downstream= 30 kmph
  downstream= speed of boat+ speed of stream
  30=15+speed of stream
  speed of stream = 15 kmph (i think its correct)
• 9 years agoHelpfull: Yes(0) No(1)
• speed of stream is 3kmph
• 9 years agoHelpfull: Yes(0) No(1)
• the question is wrong
  at the place of 30 kmph it should be 30 km only ...
  than correct answer is 5
  
  i ask u one question those who are telling answer as 15
  if the speed of boat as well as the steam both become 15 how it is possible to a boat to be come back . (it only go by a speed of 15+15=30 but while returning time speed will be 15-15= 0 so not possible to come back )
• 7 years agoHelpfull: Yes(0) No(1)