Aditya can row with the stream at $10 \text{ km/h}$ and against the stream at $6 \text{ km/h}$. His speed in still water is .......... $\text{km/h}$.

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

$A$ steamer goes downstream from one port to another in $4\, h$. It covers the same distance upstream in $5\, h$. If the speed of the stream is $2\, km/h$,then find the distance between the two ports (in $km$).

$A$ river is flowing at a speed of $5\, km/h$ in a particular direction. $A$ man,who can swim at a speed of $20\, km/h$ in still water,starts swimming along the direction of flow of the river from point $A$ and reaches another point $B$ which is at a distance of $30\, km$ from the starting point $A$. On reaching point $B$,the man turns back and starts swimming against the direction of flow of the river and stops after reaching point $A$. The total time taken by the man to complete his journey is:

$A$ man rows to a place $48 \, km$ away and comes back in $14 \, hours$. He finds that he can row $4 \, km$ with the stream in the same time as $3 \, km$ against the stream. The rate of the stream is:

$A$ man can row at a speed of $4.5 \text{ km/hr}$ in still water to a certain upstream point and back to the starting point in a river which flows at $1.5 \text{ km/hr}$. Find his average speed for the total journey in $\text{km/hr}$.