the speed of boat A is 2 km/h less than the speed of the boat B. the time taken by boat A to travel a distance of 20 km downstream is 30 min more than time taken by B to travel the same distance downstream. If the speed of the current is 1/3rd of the speed of the boat A, what is the speed of boat B?

• 8 kmph
  
  
  If speed of boat B is 'b' kmph, then speed of boat A = b-2 & speed of current=(b-2)/3
  For downstream boat A takes 30 min. or 1/2 hour more than B. so comparing downstream times,
  20/[(b-2)+ (b-2)/3] =[20/[b+(b-2)/3]] + (1/2)
  On simplifying, 2b^2-5b-88=0
  (2b+11)(b-8)=0
  b=8
  
• 9 years agoHelpfull: Yes(3) No(0)