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

$A$ 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

On a river,$Q$ is the midpoint between two points $P$ and $R$ on the same bank. $A$ boat can travel from $P$ to $Q$ and back in $12$ hours,and from $P$ to $R$ in $16$ hours $40$ minutes. How long would it take to travel from $R$ to $P$? (in hours)

$A$ boat running downstream covers a distance of $16\, km$ in $2\, hours,$ while for covering the same distance upstream,it takes $4\, hours.$ What is the speed of the boat in still water? (in $km/hr$)

In a stream running at $2 \, km/hr$,a water scooter goes $10 \, km$ upstream and back again to the starting point in $55 \, minutes$. Find the speed of the water scooter in still water (in $km/hr$).

$A$ man can swim at the rate of $4\, km/h$ in still water. If the speed of the water is $2\, km/h$,then the time taken by him to swim $10\, km$ upstream is.........$h$.