Question

A man row the upstream at 9km/h and downstream at12 km/h then the man's speed in still water and the rate of current respectively are

Answer 1

Answer:

Step-by-step explanation:

\inline \frac{Time\: taken\: in\: upstream}{Time\: taken\: in\: downstream} = \inline \frac{2}{1}

\inline \therefore \inline \frac{Downstream\: speed}{upstream\: speed} = \inline \frac{2}{1}        where  \inline \frac{B+R}{B-R}=\frac{2}{1}

B ---> speed of boat in still water

R---->speed of current

\inline \Rightarrow \frac{B}{R}=\frac{3}{1}    ( By componendo and dividendo)

\inline \Rightarrow \frac{9}{R}=\frac{3}{1}\: \: \Rightarrow R= 3\: km/h

Answer 2

Answer:

21/h km speed of man

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