$A$ boat travels $2\, km$ upstream in a stream flowing at $3\, km/h$ and then returns downstream to the starting point in $30\, minutes$. The speed of the boat in still water is........$km/h$.

$A, B$ and $C$ are situated on the bank of a river which is flowing at a constant rate. $B$ is at an equal distance from $A$ and $C$. $A$ swimmer Avinash takes $10 \, h$ to swim from $A$ to $B$ and $B$ to $A$. Also,he takes $8 \, h$ to swim from $A$ to $C$ in downstream. What is the ratio of the speed of Avinash in still water to the speed of the stream?

$A$ man can swim in still water at $9.6 \text{ km/hr}$,but takes twice as long to swim upstream as he does downstream. The speed of the stream is ......... $\text{km/hr}$.

$A$ man rows upstream $12 \text{ km}$ and downstream $28 \text{ km}$,taking $5 \text{ hours}$ each time. The velocity of the water current is ......... $\text{km/h}$.

$A$ man can row upstream $36 \text{ km}$ in $6 \text{ hours}$. If the speed of a man in still water is $8 \text{ km/hr}$,find how much distance he can cover downstream in $10 \text{ hours}$? (in $\text{km}$)

$A$ boatman takes twice as long to row a distance against the stream as to row the same distance with the stream. Find the ratio of the speed of the boat in still water to the speed of the stream.