Q. A boat whose speed is 15 k/hr in still water goes 30 k/he downwards and come back in total 4 hr 30 min what is the speed of stream in k/hr

• Ans=5 km/hr
  If the speed of stream=x
  Speed in downstream=15+x , Speed in Upstream=15-x,
  Total time=4 hr 30 min=9/2 hr
  [30/(15+x) + 30/(15-x)]=9/2,Solving x=5
• 10 years agoHelpfull: Yes(30) No(1)
• u = speed of boat in still water =15k/h
  v= speed of stream = ?
  downstream speed of boat = u+v = 30k/h
  so, v= (u+v)-u=15k/h
• 10 years agoHelpfull: Yes(3) No(14)
• speed upstream=(u+v)=(15+x)
  speed downstream=(u-v)=(15-x)
  time=9/2 m/sec (converted)
  30/15+x +30/15-x=9/2
  solve the equation u can get answer !!!
• 10 years agoHelpfull: Yes(2) No(0)
• let speed of stream =x km/hr so according to the formula,
  30/(15+x)+30/(15-x)=9/2
  30[30/225-x^2]=9/2
  225-x^2=900*2/9=200
  x^2=25, x=5km/hr
• 10 years agoHelpfull: Yes(1) No(0)