$A$ car covers the first $39 \, km$ of its journey in $45 \, minutes$ and the remaining $25 \, km$ in $35 \, minutes$. What is the average speed of the car in $km/h$?

$A$ horse rider travels on horseback from Bhopal to Chandigarh at a constant speed. If the horse increased its speed by $6 \, km/h$,it would take the rider $4 \, hours$ less to cover that distance. If the horse travelled at a speed $6 \, km/h$ lower than the initial speed,it would take him $10 \, hours$ more than the time he would have taken if he had travelled at a speed $6 \, km/h$ higher than the initial speed. Find the distance between Bhopal and Chandigarh in $km$.

Two trains of equal length take $10\, seconds$ and $15\, seconds$ respectively to cross a telegraph post. If the length of each train is $120\, metres,$ in what time (in $seconds$) will they cross each other when travelling in opposite directions?

$A$ train can travel $50\%$ faster than a bus. Both start from point $A$ at the same time and reach point $B$ at the same time. Point $B$ is $75 \, km$ away from point $A$. On the way, the train stops for $12.5 \, minutes$. The speed of the bus is (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. Find the correct time for the train to complete its journey (in minutes).

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 $\text{km/h}$):