$A$ bus travels $720 \text{ km}$ in $20 \text{ hours}$. Calculate its average speed in $\text{metres/seconds}$.

$A$ car travels the first $39 \, km$ distance in $45 \, minutes$ and the next $25 \, km$ distance in $35 \, minutes$. What is its average speed in $km/h$?

Two cyclists started simultaneously towards each other and meet each other $3$ hours $20$ minutes later. How much time will it take the slower cyclist to cover the whole distance if the first arrived at the place of departure of the second $5$ hours later than the second arrived at the point of departure of the first? (in hours)

$A$ car travels from $P$ to $Q$ at a constant speed. If its speed were increased by $10 \, km/h$,it would have taken $1 \, hour$ less to cover the distance. It would have taken a further $45 \, minutes$ less if the speed was increased by another $10 \, km/h$. The distance between the two cities is (in $km$):

$A$ $180\, m$ 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 $km/h$?

$A$ walks around a circular field at the rate of one $round/hour$,while $B$ runs around it at the rate of six $rounds/hour$. They start in the same direction from the same point at $7.30 \, a.m$. They shall first cross each other at (in $a.m.$)