$A$ boat goes $13\, km$ upstream in $39\, minutes$. The speed of the stream is $3\, km/h$. The speed of the boat in still water is......$km/h$.

$A$ motor-boat,travelling at the same speed,can cover $25\, km$ upstream and $39\, km$ downstream in $8\, hours$. At the same speed,it can travel $35\, km$ upstream and $52\, km$ downstream in $11\, hours$. The speed of the stream is $........\, km/h$.

$A$ boat goes $40\, km$ upstream in $8\, h$ and $36\, km$ downstream in $6\, h$. The speed of the boat in still water is......$km/h$

The speed of a boat in still water is $7\, km/h$. If its speed in downstream is $10\, km/h$,then the speed of the stream is .......... $km/h$.

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 $km/h$).

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 $\text{ hours}$)