$A$ man travelled a distance of $80\, km$ in $7\, hours$,partly on foot at the rate of $8\, km/h$ and partly on bicycle at $16\, km/h$. The distance travelled on foot is (in $km$):

Walking $\frac{6}{7}$ of his usual speed, a man is $12 \, \text{minutes}$ late. The usual time taken by him to cover that distance is

$A$ and $B$ are two stations. $A$ train goes from $A$ to $B$ at $64 \text{ km/h}$ and returns to $A$ at a slower speed. If its average speed for the whole journey is $56 \text{ km/h}$,at what speed did it return? (in $\text{km/h}$)

How many seconds will a $500 \, m$ long train take to cross a man walking with a speed of $3 \, km/h$ in the direction of the moving train, if the speed of the train is $63 \, km/h$?

If a person walks at $14 \, km/hr$ instead of $10 \, km/hr$,he would have walked $20 \, km$ more. The actual distance travelled by him is (in $km$)

$A$ bike covers a certain distance at a speed of $64 \, km/h$ in $8 \, hours$. If the bike were to cover the same distance in approximately $6 \, hours$,at what approximate speed should the bike travel? (in $km/h$)