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

$A$ man travels $360 \, km$ in $4 \, hrs$,partly by air and partly by train. If he had travelled all the way by air,he would have saved $\frac{4}{5}$ of the time he was in train and would have arrived at his destination $2 \, hrs$ early. Find the distance he travelled by train (in $km$).

$A$ moving train crosses a man standing on a platform and a bridge of $300 \, \text{metres}$ long in $10 \, \text{seconds}$ and $25 \, \text{seconds}$ respectively. What will be the time taken by the train to cross a platform $200 \, \text{metres}$ long? (in $\text{seconds}$)

$A$ train running at $\frac{7}{11}$ of its normal speed reached a place in $22\, \text{hours}$. How much time could be saved if the train had run at its normal speed? (in $\text{hours}$)

$A$ car is running at a speed of $108 \, km/hr$. What distance will it cover in $15 \, s$? (in $meters$)

What is the speed of the train in $km/h$?
Statements:
$I.$ The train crosses an $x$ meter-long platform in $n$ seconds.
$II.$ The length of the train is $y$ meters.
$III.$ The train crosses a signal pole in $m$ seconds.