$A$ boat goes $48\, km$ downstream in $20\, h$. It takes $4\, h$ more to cover the same distance against the stream. What is the speed of the boat in still water? (in $km/h$)

The speed of a boat in still water is $4 \, km/h$ and the speed of the current is $2 \, km/h$. If the time taken to reach a certain distance upstream is $9 \, hours$,find the time it will take to go the same distance downstream (in $hrs$).

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.

In a fixed time,a boy swims double the distance along the current that he swims against the current. If the speed of the current is $3 \text{ km/h}$,then find the rate of swimming in still water in $\text{km/h}$.

$A$ man can row $9 \text{ km/hr}$ in still water. If the river is running at $3 \text{ km/hr}$,it takes $3 \text{ hours}$ more to row upstream than to row downstream for the same distance. How far is the place? (in $\text{km}$)

$A$ man moves $20 \, km$ downstream in $5 \, hours$ and $10 \, km$ upstream in the same time. The speed of the stream is...........$km/h$.