$A$ train $800 \, m$ long is running at a speed of $78 \, km/h$. If it crosses a tunnel in $1 \, minute$,then the length of the tunnel (in $m$) is:

$A$ man walks $6 \, km$ at a speed of $1 \frac{1}{2} \, km/h$,runs $8 \, km$ at a speed of $2 \, km/h$,and travels another $32 \, km$ by bus. The speed of the bus is $8 \, km/h$. Find the average speed of the man in $km/h$.

$A$ train completes a non-stop journey in $8 \, \text{hours}$. If it had travelled $5 \, \text{km/h}$ faster, it would have completed the journey in $6 \, \text{hours} \, 40 \, \text{minutes}$. What is its lowest speed in $\text{km/h}$?

$A$ student walks from his house at $5 \, km/h$ and reaches his school $10 \, minutes$ late. If his speed had been $6 \, km/h$,he would have reached $15 \, minutes$ early. The distance of his school from his house is (in $km$):

$A$ person travelled a certain distance by train at a speed of $25\, km/h$ and walked back at a speed of $4\, km/h$. The whole journey took $5\, hours\, 48\, minutes$. What distance did he travel? (in $km$)

$A$ student goes to school at the rate of $2 \frac{1}{2} \text{ km/h}$ and reaches $6 \text{ min}$ late. If he travels at the speed of $3 \text{ km/h}$,he is $10 \text{ min}$ early. The distance (in $\text{km}$) between the school and his house is: