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 $.5$)?

$A$ $180\, m$ long train crosses another $270\, m$ long train running in the opposite direction in $10.8\, seconds$. If the speed of the first train is $60\, km/h$, what is the speed of the second train in $km/h$?

$A$ motor car completes a journey in $10 \, hours$. It covers the first half of the distance at $21 \, km/h$ and the remaining half at $24 \, km/h$. Find the total distance (in $km$).

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.

It takes $8\, hours$ for a $600\, km$ journey,if $120\, km$ is done by train and the rest by car. It takes $20\, minutes$ more,if $200\, km$ is done by train and the rest by car. The ratio of the speed of the train to that of the car is

Train $A$ crosses a pole in $25 \text{ seconds}$ and another Train $B$ crosses a pole in $1 \text{ minute}$ and $15 \text{ seconds}$. The length of Train $A$ is half the length of Train $B$. What is the respective ratio between the speeds of Train $A$ and Train $B$?