Excluding stoppages, the speed of a bus is $54 \, km/h$ and including stoppages, it is $45 \, km/h$. For how many minutes does the bus stop per hour?

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.

$A$ train running at a speed of $60\, km/h$ crosses a platform double its length in $32.4\, seconds.$ What is the length of the platform? (in $m$)

Two trains measuring $100\, m$ and $80\, m$ respectively,run on parallel tracks. When travelling in opposite directions,they are observed to pass each other in $9\, s$. When they are running in the same direction at the same speeds as before,the faster train passes the other in $18\, s$. Find the speeds of the two trains in $km/h$.

If a train runs at $40 \text{ km/h}$,it reaches its destination late by $11 \text{ minutes}$. But if it runs at $50 \text{ km/h}$,it is late by $5 \text{ minutes}$ only. The correct time (in $\text{minutes}$) for the train to complete the journey is

Starting from his house,a student walks at a speed of $2.5 \, km/hr$ and reaches his school $6 \, minutes$ late. Next day he increases his speed by $1 \, km/hr$ and reaches the school $6 \, minutes$ early. How far is the school from his house? (in $km$)