$A$ 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?

$A$ policeman starts to chase a thief. When the thief goes $10 \, \text{steps}$, the policeman moves $8 \, \text{steps}$. $5 \, \text{steps}$ of the policeman are equal to $7 \, \text{steps}$ of the thief. The ratio of the speeds of the policeman and the thief is

Walking at the rate of $4 \, km/h$, a man covers a certain distance in $2 \, \text{hours} \, 45 \, \text{minutes}$. Running at a speed of $16.5 \, km/h$, the man will cover the same distance in how many minutes?

If the length of the train is $700 \, m$ and the length of the platform is $500 \, m$,find the time taken by the train moving at $54 \, km/h$ to cross the platform (in $sec$).

$A$ $320\, m$ long train moving at an average speed of $120\, km/h$ crosses a platform in $24\, seconds$. $A$ man crosses the same platform in $4\, minutes$. What is the speed of the man in $m/s$?

$A$ $135\, m$ long train is running with a speed of $54\, km/h$. In what time will it pass a telegraph post? (in $seconds$)