$A$ boat can travel with a speed of $13 \text{ km/hr}$ in still water. If the speed of the stream is $4 \text{ km/hr}$,the time taken by the boat to travel $63 \text{ km}$ in the opposite direction (upstream) is........$hrs$.

$A$ boat travels $60$ km downstream and $20$ km upstream in $4$ hours. The same boat travels $40$ km downstream and $40$ km upstream in $6$ hours. What is the speed (in $km/hr$) of the stream?

There is a road beside a river. Two friends started from a place $A,$ moved to a temple situated at another place $B$ and then returned to $A$ again. One of them moves on a cycle at a speed of $12\, km/hr,$ while the other sails on a boat at a speed of $10\, km/hr.$ If the river flows at the speed of $4\, km/hr,$ which of the two friends will return to place $A$ first?

In a river flowing at $2\, km/h$, a boat travels $32\, km$ upstream and then returns downstream to the starting point. If its speed in still water is $6\, km/h$, find the total journey time in hours.

$A$ 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:

Speed of a boat is $5 \, km/h$ in still water and the speed of the stream is $3 \, km/h$. If the boat takes $3 \, h$ to go to a place and come back,the distance of the place is ....... $km$.