$A$ man can row $18 \ km/h$ in still water. It takes him thrice as long to row up as to row down the river. Find the rate of the stream. (in $km/h$)

$A$ boat covered a certain distance travelling downstream in $45$ $minutes,$ while it came back to the starting point in $1$ $hour$ $15$ $minutes.$ The speed of the stream is $2$ $kmph.$ What is the speed of the boat in still water? (in $kmph$)

$A$ man can row $6 \, km/h$ in still water. If the speed of the current is $2 \, km/h$,it takes $3 \, h$ more in upstream than in the downstream for the same distance. The distance is......$km$.

$A$ boat can travel with a speed of $13\, km/hr$ in still water. If the speed of the stream is $4\, km/hr,$ find the time taken by the boat to go $68\, km$ downstream. (in $hours$)

$A$ boatman can row $48\, km$ downstream in $4\, hours$. If the speed of the current is $5\, km/h$,then find in what time will he be able to cover $8\, km$ upstream? (in $hours$)

$A$ man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is: