$A$ man can swim at the rate of $4\, km/h$ in still water. If the speed of the water is $2\, km/h$,then the time taken by him to swim $10\, km$ upstream is.........$h$.

$A$ man can row at a speed of $15\, km/hr$ in still water to a certain upstream point and back to the starting point in a river which flows at $3\, km/hr$. Find his average speed for the total journey (in $km/hr$).

Speed of a motorboat in still water is $45\, km/h$. If the motorboat travels $80\, km$ along the stream in $1\, h\, 20\, min$,then the time taken by it to cover the same distance against the stream will be:

$A$ man can row $30 \text{ km}$ upstream and $44 \text{ km}$ downstream in $10 \text{ hours}$. Also,he can row $40 \text{ km}$ upstream and $55 \text{ km}$ downstream in $13 \text{ hours}$. Find the rate of the current and the speed of the man in still water (in $\text{km/h}$).

$A$ man can row $9 \text{ km/hr}$ in still water. If the river is running at $3 \text{ km/hr}$,it takes $3 \text{ hours}$ more to row upstream than to row downstream for the same distance. How far is the place? (in $\text{km}$)

In a stream running at $2 \, km/h$,a motorboat goes $10 \, km$ upstream and returns to the starting point in $55 \, min$. Find the speed of the motorboat in still water (in $km/h$).