A boat covers a certain distance against the stream in 9 hours 36 min and it covers the same distance along the stream in 6 hours. What is the ratio of the speed of the boat in still water to that of the stream?
Answer & explanation
Correct answer: option 1
Ratio of time = 576 : 360
= 8 : 5
As distance is same so the speed is inversely proportional to time.
So , Ratio of speed = 5 : 8
Let upstream speed = 5R
downstream speed = 8R
We know ,
Speed of boat = \(\frac{Upstream \; speed \;+ Downstream \;speed}{2}\)
Spped of Stream = \(\frac{Downstream \; speed \;+ Upstream \;speed}{2}\)
From here speed of boat = \(\frac{8R+ 5R}{2}\)= \(\frac{13R}{2}\)
And speed of stream = \(\frac{8R - 5R}{2}\) = \(\frac{3R}{2}\)
Hence , Required ratio will be = 13 : 3