$A$ man travels a distance of $24 \, km$ at $6 \, km/h$,another distance of $24 \, km$ at $8 \, km/h$,and a third distance of $24 \, km$ at $12 \, km/h$. His average speed for the whole journey (in $km/h$) is?

The distance between places $A$ and $B$ is $999 \, km$. An express train leaves place $A$ at $6 \, am$ and runs at a speed of $55.5 \, km/h$. The train stops on the way for $1 \, hr \, 20 \, min$. It reaches $B$ at?

$A$ truck covers a distance of $396 \, km$ in $5 \, hours \, 30 \, minutes$. The average speed of a bike is $\frac{4}{3}$ of the average speed of the truck. What is the time taken by the bike to cover a distance of $12 \, km$ less than the distance covered by the truck?

Train $A$ crosses a stationary Train $B$ in $50 \text{ seconds}$ and a pole in $20 \text{ seconds}$ with the same speed. The length of Train $A$ is $240 \text{ meters}$. What is the length of the stationary Train $B$ (in meters)?

Deepa drives a bike at an average speed of $30 \, km/h$ and reaches her destination in $6 \, hours$. Hema covers that same distance in $4 \, hours$. If Deepa increases her average speed by $10 \, km/h$ and Hema increases her average speed by $5 \, km/h$,then what will be the difference in time taken by them to reach their destination?

$A$ car completes a journey in $6\, hours$. It covers half the distance at $50\, km/h$ and the rest at $70\, km/h$. The length of the journey is (in $km$):