$A$ $280 \, m$ 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 $m/s$?

Two trains of equal length are running on parallel tracks in the same direction at the speeds of $46 \, km/h$ and $36 \, km/h$. The faster train passes the slower train in $36 \, seconds$. The length of each train is (in $m$):

$A$ person goes from point $A$ to $B$ with a speed of $55 \text{ km/hr}$ and returns with a speed of $65 \text{ km/hr}$. What is the average speed (in $\text{km/hr}$) of the person while going and coming back from $A$ to $B$?

$A$ person has to reach a certain place at a certain time. He finds that he will be $15 \text{ minutes}$ late if he walks at $4 \text{ km/h}$,and $10 \text{ minutes}$ earlier if he walks at $6 \text{ km/h}$. How far has he to walk? (in $\text{km}$)

$A$ train completes a non-stop journey in $8 \, \text{hours}$. If it had travelled $5 \, \text{km/h}$ faster, it would have completed the journey in $6 \, \text{hours} \, 40 \, \text{minutes}$. What is its lowest speed in $\text{km/h}$?

$A$ train $150 \, m$ long is running at $95 \, km/h$. How much time will it take to pass a man moving in the same direction at $5 \, km/h$? (in $seconds$)