Two trains,one $160 \, m$ and the other $140 \, m$ long,are running in opposite directions on parallel tracks. The first is moving at $77 \, km/h$ and the other at $67 \, km/h$. How long will they take to cross each other? (in $seconds$)

Two trains are running in opposite directions with speeds of $62 \, km/h$ and $40 \, km/h$,respectively. If the length of one train is $250 \, m$ and they cross each other in $18 \, seconds$,then the length of the other train is (in $m$):

$A$ man standing on a railway platform observes that a train going in one direction takes $4 \,seconds$ to pass him. Another train of the same length going in the opposite direction takes $5 \,seconds$ to pass him. The time taken (in $seconds$) by the two trains to cross each other will be:

$A$ man driving at $\frac{3}{4}$ of his original speed reaches his destination $20 \text{ minutes}$ later than the usual time. Then the usual time is (in $\text{minutes}$)

The distance of the sun from the earth is $143,400,000 \text{ km}$. Light travels from the sun to the earth in $7 \text{ minutes}$ and $58 \text{ seconds}$. The velocity of light per second is (in $\times 10^5 \text{ km/sec}$):

$A$ thief is stopped by a policeman from a distance of $150\, m$. When the policeman starts the chase,the thief also starts running. Assuming the speed of the thief as $7\, km/h$ and that of the policeman as $9\, km/h$,how far would the thief have run before he is overtaken by the policeman? (in $m$)