$A$ $280 \, m$ long train moving with an average speed of $108 \, km/h$ crosses a platform in $12 \, s$. $A$ man crosses the same platform in $10 \, s$. What is the speed of the man in $m/s$?

The ratio of the speed of a bus to that of a train is $15: 27$. Also,a car covered a distance of $720 \text{ km}$ in $9 \text{ hours}$. The speed of the bus is $\frac{3}{4}$ the speed of the car. How much distance will the train cover in $7 \text{ hours}$? (in $\text{km}$)

$A$ farmer travelled a distance of $61 \, km$ in $9 \, hrs$. He travelled partly on foot at the rate of $4 \, km/hr$ and partly on bicycle at the rate of $9 \, km/hr$. The distance travelled on foot is (in $km$):

$A$ and $B$ are two towns. $A$ car goes from $A$ to $B$ at a speed of $64 \, km/h$ and returns to $A$ at a slower speed. If its average speed for the whole journey is $56 \, km/h$,find its return speed (in $km/h$).

$A$ train running at a speed of $40 \, m/s$ crosses a pole in $21 \, s$ less than the time it requires to cross a bridge $3.5$ times its length at the same speed. What is the length of the bridge (in $m$)?

$A$ boy goes to his school from his house at a speed of $3 \, km/hr$ and returns at a speed of $2 \, km/hr$. If he takes $5 \, hours$ in total for the round trip,the distance between his house and school is (in $km$):