If a man's rate with the current is $12\, km/h$ and the rate of current is $1.5\, km/h$,then the man's rate against the current in $km/h$ is...........

$A$ person can swim in still water at $4 \, km/h$. If the speed of the water current is $2 \, km/h$,how many hours will the man take to swim back against the current for $6 \, km$?

The speed of a boat in still water is $10\, km/h$. It covers an upstream distance of $45\, km$ in $6\, h$. The speed (in $km/h$) of the stream is:

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

The speed of a boat in still water is $10\, km/hr$. If it can travel $26\, km$ downstream and $14\, km$ upstream in the same time,the speed of the stream is.....$km/hr$.

In a stream running at $2 \, km/h$,a motorboat goes $10 \, km$ upstream and returns to the starting point in $55 \, min$. Find the speed of the motorboat in still water (in $km/h$).