$A$ man can row $30 \text{ km}$ downstream and return in a total of $8 \text{ h}$. If the speed of the boat in still water is $4$ times the speed of the current,then the speed of the current is ....... $\text{km/h}$.

$A$ person can row a certain distance downstream in $6$ $hours$ and return the same distance in $9$ $hours.$ If the stream flows at the rate of $2 \frac{1}{4} \text{ km/h},$ find how far he can row in an hour in still water (in $\text{km/h}$).

$A$ man can row at $5 \, km/h$ in still water and the velocity of the current is $1 \, km/h$. It takes him $1 \, hour$ to row to a place and back. How far is the place? (in $km$)

Keshav can row $60 \ km$ downstream and $36 \ km$ upstream,taking $10 \ h$ each time. What is the velocity of the current? (in $km/h$)

$A$ man can swim $3 \text{ km/h}$ in still water. If the velocity of the stream is $2 \text{ km/h}$,the time taken by him to swim to a place $10 \text{ km}$ upstream and back is (in hours):

The speed of a boat in still water is $6\, km/h$. It takes the boat twice as long to row up as to row down the river. Find the rate of the stream (in $km/h$).