$A$ bus moving at a speed of $45 \, km/h$ overtakes a truck $150 \, m$ ahead going in the same direction in $30 \, s.$ The speed of the truck is? (in $km/h$)

$A$ person covers half of his journey at $30 \text{ km/h}$ and the remaining half at $20 \text{ km/h}$. The average speed for the whole journey is (in $\text{km/h}$)

An aeroplane covers a certain distance at a speed of $240 \text{ km/h}$ in $5 \text{ hours}$. To cover the same distance in $1 \frac{2}{3} \text{ hours}$,it must travel at a speed of (in $\text{km/h}$):

$A$ man walks at the rate of $5 \, km/hr$ for $6 \, hours$ and at $4 \, km/hr$ for $12 \, hours$. The average speed of the man (in $km/hr$) is:

Two places $P$ and $Q$ are $162 \, km$ apart. $A$ train leaves $P$ for $Q$ and simultaneously another train leaves $Q$ for $P$. They meet at the end of $6 \, hours$. If the former train travels $8 \, km/h$ faster than the other,then the speed of the train from $Q$ is (in $km/h$):

$A$ thief is noticed by a policeman from a distance of $200\, m$. The thief starts running and the policeman chases him. The thief and the policeman run at the speed of $10\, km/h$ and $11\, km/h$ respectively. What is the distance between them after $6\, minutes$? (in $m$)