Twice the speed downstream is equal to thrice the speed upstream. The ratio of the speed in still water to the speed of the current is:

Speed of a boat in standing water is $9 \text{ km/h}$ and the speed of the stream is $1.5 \text{ km/h}$. $A$ man rows to a place at a distance of $105 \text{ km}$ and comes back to the starting point. The total time taken by him is (in $\text{ hours}$)

$A$ man can swim $3 \text{ km/h}$ in still water. If the velocity of the stream is $2 \text{ km/h}$,the time taken by him to swim to a place $10 \text{ km}$ upstream and back is (in hours):

The current of a stream runs at the rate of $4 \text{ km/h}$. $A$ boat goes $6 \text{ km}$ and comes back to the starting point in $2 \text{ hours}$. The speed of the boat in still water is ....... $\text{km/h}$.

$A$ 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.........$h$.

$A$ boat goes $6\, km$ upstream and back again to the starting point in $2\, hours$. If the velocity of the stream is $4\, km/hr$,what is the speed of the boat in still water? (in $km/hr$)