$A$ train running at the speed of $60 \; km/hr$ crosses a pole in $9 \; seconds$. What is the length (in $m$) of the train?

How many seconds will a train $60 \; m$ in length,travelling at the rate of $42 \; km/h$,take to pass another train $84 \; m$ long,proceeding in the same direction at the rate of $30 \; km/h$?

$A$ train $125 \;m$ long passes a man,running at $5 \;km/hr$ in the same direction in which the train is going,in $10 \;seconds$. The speed of the train is (in $km/hr$):

Two trains of equal lengths take $10 \; s$ and $15 \; s$ respectively to cross a telegraph post. If the length of each train is $120 \; m$,in what time (in $s$) will they cross each other when travelling in opposite directions?

Two trains,each $100 \; m$ long,moving in opposite directions,cross each other in $8 \; s$. If one is moving twice as fast as the other,then the speed (in $km/h$) of the faster train is:

Two stations $P$ and $Q$ are $110 \; km$ apart on a straight line. One train starts from $P$ at $7 \; am$ and travels towards $Q$ at $20 \; km/h$ speed. Another train starts from $Q$ at $8 \; am$ and travels towards $P$ at a speed of $25 \; km/h$. At what time will they meet?