In one hour,a boat goes $11 \ km$ along the stream and $5 \ km$ against the stream. The speed of the boat in still water (in $km/hr$) is

$A$ boat covers a certain distance downstream in $1 \text{ hour}$,while it comes back in $1.5 \text{ hours}$. If the speed of the stream is $3 \text{ km/hr}$,what is the speed of the boat in still water? (in $\text{km/hr}$)

$A$ man can row a boat at a speed of $8\, km/h$ in still water. He was rowing the boat downstream from one point to another. After travelling half of the distance,the motor of the boat failed. He continued to drift along the stream and reached his destination,taking $6\, hours$ more than the usual time. The speed of the stream is $2\, km/h$. What is the total distance between the two points in $km$?

$A$ boatman rows $1\, km$ in $5\, min$ along the stream and $6\, km$ in $1\, h$ against the stream. The speed of the stream is $km/h$.

$A$ boat covers $24 \text{ km}$ upstream and $36 \text{ km}$ downstream in $6 \text{ hours}$,while it covers $36 \text{ km}$ upstream and $24 \text{ km}$ downstream in $6 \frac{1}{2} \text{ hours}$. The velocity of the current is .... $\text{km/h}$.

Speed of a man is $10 \text{ km/h}$ in still water. If the rate of current is $3 \text{ km/h}$,then the effective speed of the man upstream is ....... $\text{km/h}$.