$A$ train running at the speed of $84 \, km/h$ passes a man walking in the opposite direction at the speed of $6 \, km/h$ in $4 \, s$. What is the length of the train (in $meters$)?

On a tour,a man travels at the rate of $64 \text{ km/h}$ for the first $160 \text{ km}$,then travels the next $160 \text{ km}$ at the rate of $80 \text{ km/h}$. The average speed in $\text{km/h}$ for the first $320 \text{ km}$ of the tour is:

$A$ train $700 \, m$ long is running at a speed of $72 \, km/hr$. If it crosses a tunnel in $1 \, minute$,then the length of the tunnel (in $metres$) is:

The ratio of the speeds of a car,a train,and a bus is $5:9:4$. The average speed of the car,the bus,and the train together is $72 \text{ km/h}$. What is the average speed of the car and the train together? (in $\text{km/h}$)

$A$ man leaves a point $P$ and reaches the point $Q$ in $4 \, hours$. Another man leaves the point $Q$,$2 \, hours$ earlier and reaches the point $P$ in $4 \, hours$. Find the time in which the first man meets the second man (in $hours$).

$A$ train of length $100\, m$ crosses another train of length $150\, m,$ running on a parallel track in the opposite direction in $9\, s.$ If the speed of the train having length $150\, m$ is $40\, km/h,$ what is the speed (in $km/h$) of the other train?