$A$ man can row at a speed of $4.5 \text{ km/hr}$ in still water to a certain upstream point and back to the starting point in a river which flows at $1.5 \text{ km/hr}$. Find his average speed for the total journey in $\text{km/hr}$.

Speed of a motorboat in still water is $45 \text{ km/h}$. If the motorboat travels $80 \text{ km}$ along the stream in $1 \text{ h } 20 \text{ min}$,then the time taken by it to cover the same distance against the stream will be:

$A$ man can row with the stream at $7\, km/h$ and against the stream at $3\, km/h$. His speed in still water is.......$km/h$

$A$ boat moves downstream at the rate of $1 \, km$ in $7 \frac{1}{2} \, \text{minutes}$ and upstream at the rate of $5 \, km/h$. What is the speed (in $km/h$) of the boat in still water?

$A$ man rows at $9 \frac{1}{3} \text{ km/h}$ in still water and finds that it takes him thrice as much time to row up than to row down the same distance in the river. The speed of the current is.......$\text{km/h}$

Rahul can travel $12 \text{ miles}$ downstream in a certain river in $6 \text{ hours}$ less than it takes him to travel the same distance upstream. But if he could double his usual rowing rate for his $24 \text{ mile}$ round trip,the downstream $12 \text{ miles}$ would take only one hour less than the upstream $12 \text{ miles}$. What is the speed of the current in $\text{miles/hour}$?