Relative Speed Questions

A policeman chases a thief who is running at a speed of $7\text{km/h}$. The speed of the policeman is $12\text{km/h}$. If the thief is $280\text{meters}$ ahead of the policeman, then how much time will the policeman take to catch the thief?

A man wants to cover a distance of $1\text{km}$ in a river. It takes him $12\text{minutes}$ to cover this distance in still water, but it takes $13\text{minutes}$ in the flowing river. Find the speed of the flowing water of the river.

A thief running at $7\text{km/h}$ is chased by a policeman whose speed is $12\text{km/h}$. If the thief is $280\text{m}$ ahead of the policeman, then the time required for the policeman to catch the thief will be:

A $255\text{m}$ long train is running at a speed of $72\text{km/h}$. It crosses a platform of length $745\text{m}$ in: