$A$ $110 \text{ meters}$ long train passes a man walking at the speed of $6 \text{ km/h}$ against it in $6 \text{ seconds}$. The speed of the train in $\text{km/h}$ is:

$A, B$ and $C$ start at the same time in the same direction to run around a circular stadium. $A$ completes a round in $252 \text{ seconds}$,$B$ in $308 \text{ seconds}$ and $C$ in $198 \text{ seconds}$,all starting at the same point. After what time will they next meet at the starting point again?

Two trains started at the same time,one from $A$ to $B$ and the other from $B$ to $A$. If they arrived at $B$ and $A$ respectively $4 \ hours$ and $9 \ hours$ after they passed each other,the ratio of the speeds of the two trains was:

$A$ man travels $600 \, km$ by train at $80 \, km/hr$, $800 \, km$ by ship at $40 \, km/hr$, $500 \, km$ by aeroplane at $400 \, km/hr$, and $100 \, km$ by car at $50 \, km/hr$. What is the average speed for the entire distance? (in $km/hr$)

$A$ car moving in the same direction passes a man walking at $4\, km/h$. The man can see the car for $3\, minutes$ and the visibility is up to a distance of $130\, m$. The speed of the car is: (in $km/h$)

$A$ man takes $6\, h \, 15\, min$ in walking a distance and riding back to the starting place. He could walk both ways in $7\, h \, 45\, min$. The time taken by him to ride both ways is: