Question

A boat covers a certain distance downstream in 1 hour while it comes back in $1\frac{1}{2}$ hours If the speed of the stream be 3 kmph what is the speed of the boat in still water?

Answer 1

Let the speed of the boat in still ater be $x$ kmph

Then Speed downstream = $(x+3)$ kmph

Speed upstream = $(x-3)$ kmph

$\therefore (x+3)\times 1=(x-3)\times \frac{3}{2}\Rightarrow 2x+6=3x-9\Rightarrow x=15$ kmph