$A$ man rows a boat $18 \ km$ in $4 \ h$ downstream and returns upstream in $12 \ h$. The speed of the stream (in $km/h$) is

$A$ man takes $3$ $hours$ $45$ $minutes$ to row a boat $15 \; km$ downstream of a river and $2$ $hours$ $30$ $minutes$ to cover a distance of $5 \; km$ upstream. Find the speed of the river current in $km/hr$.

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 $km/h$).

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

$A$ boat running downstream covers a distance of $20\, km$ in $2\, h$ while it covers the same distance upstream in $5\, h$. Then,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 .......... $km/h$.