$A$ man travelled from the village to the post office at the rate of $25 \, km/hr$ and walked back at the rate of $4 \, km/hr$. If the whole journey took $5 \, hours \, 48 \, minutes$,find the distance of the post office from the village (in $km$).

$A$ train covers a distance of $12 \, km$ in $10 \, minutes$. If it takes $6 \, seconds$ to pass a telegraph post,then the length of the train is (in $meters$):

The call rate of a $SIM$ of Company $A$ is one paisa for every three seconds. Another $SIM$ of Company $B$ charges $45 \text{ paisa per minute}$. $A$ man talked for $591 \text{ seconds}$ from the $SIM$ of Company $A$ and $780 \text{ seconds}$ from the $SIM$ of Company $B$. What would be the total amount he spent? (in $Rs.$)

The speed of a car increases by $2\, km/h$ after every hour. If the distance travelled in the first hour was $35\, km$,what is the total distance travelled in $12$ hours? (in $km$)

$A$ person covers a certain distance in $6 \, hours$ if he travels at $40 \, km/h$. If he has to cover the same distance in $4 \, hours$,then his speed must be (in $km/h$):

Rajesh covers a certain distance by bus at $16 \text{ km/h}$ and returns to the starting point on a cycle at $9 \text{ km/h}$. His average speed for the whole journey is (in $\text{km/h}$):