$A$ train travels $225 \ km$ in $3.5 \ hours$ and $370 \ km$ in $5 \ hours.$ Find out the average speed of the train in $km/h$.

With a uniform speed,a car covers a certain distance in $8 \, hours$. Had the speed been increased by $4 \, km/hr$,the same distance could have been covered in $7.5 \, hours$. What is the distance covered? (in $km$)

$A$ train $200 \, m$ long is running at a speed of $20 \, m/s$. In how much time (in $seconds$) will it cross a bridge of $400 \, m$ length?

$A, B$ and $C$ can walk at the rates of $3, 4$ and $5 \text{ km/h}$ respectively. They start from Pune at $1, 2$ and $3 \text{ o'clock}$ respectively. When $B$ catches $A$,$B$ sends him back with a message to $C$. When will $C$ get the message?

$A$ 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 $seconds$)

$A, B$ 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?