Two trains are moving in the same direction at $50 \, km/h$ and $30 \, km/h$. The faster train crosses a man in the slower train in $18 \, seconds$. Find the length of the faster train (in $m$).

$A$ thief is spotted by a policeman from a distance of $200 \text{ meters}$. When the policeman starts to chase the thief,the thief also starts running. Assuming the speed of the thief is $10 \text{ km/h}$ and that of the policeman is $12 \text{ km/h}$,how far will the thief have run before he is overtaken by the policeman? (in $\text{km}$)

Two men $A$ and $B$ start from a place $P$ walking at $3 \, km/h$ and $3.5 \, km/h$ respectively. How many $km$ will they be apart at the end of $3 \, h$,if they walk in opposite directions (in $.5$)?

$A$ train covers a distance between station $A$ and station $B$ in $45\, minutes.$ If the speed of the train is reduced by $5\, km/h,$ then the same distance is covered in $48\, minutes.$ The distance between stations $A$ and $B$ is (in $km$):

$A$ student goes to school at the rate of $2 \frac{1}{2} \text{ km/h}$ and reaches $6 \text{ min}$ late. If he travels at the speed of $3 \text{ km/h}$,he is $10 \text{ min}$ early. The distance (in $\text{km}$) between the school and his house is:

Two boys jointly begin to write a booklet containing $817$ lines. The first boy starts with the first line and writes $200$ lines an hour. The second boy starts with the last line,then writes line $816$ and so on,proceeding backwards at the rate of $150$ lines an hour. They will meet on: