$A$ boat takes half the time to travel a certain distance downstream compared to upstream. The ratio of the speed of the boat in still water to the speed of the current is:

Aditya can row with the stream at $10 \text{ km/h}$ and against the stream at $6 \text{ km/h}$. His speed in still water is .......... $\text{km/h}$.

The speed of a boat in still water is $9\, km/h$ and the speed of the stream is $1.5\, km/h$. $A$ man rows to a place at a distance of $105\, km$ and comes back to the starting point. What is the total time taken by him?

If a man's rate with the current is $12 \text{ km/h}$ and the rate of the current is $1 \frac{1}{2} \text{ km/h}$,then his rate against the current is ...... $\text{km/h}$.

Speed of a man is $12 \text{ km/h}$ in still water. If the rate of current is $4 \text{ km/h}$,then the effective speed of the man upstream is ......... $\text{km/h}$.

$A$ man can row against the current $\frac{3}{4}$ of a kilometre in $15$ minutes and returns the same distance in $10$ minutes. The ratio of his speed to that of the current is