$A$ train,when moving at an average speed of $40 \, km/hr$,reaches its destination on time. When its average speed becomes $35 \, km/hr$,it reaches its destination $15 \, minutes$ late. Find the length of the journey in $km$.

$A$ man travels first $50 \, km$ at $25 \, kmph$, next $40 \, km$ at $20 \, kmph$, and then $90 \, km$ at $15 \, kmph$. His average speed for the whole journey (in $kmph$) is:

$A$ policeman starts to chase a thief. When the thief goes $10 \, \text{steps}$, the policeman moves $8 \, \text{steps}$. $5 \, \text{steps}$ of the policeman are equal to $7 \, \text{steps}$ of the thief. The ratio of the speeds of the policeman and the thief is

$A$ hare sees a dog $100\, m$ away from her and runs off in the opposite direction at a speed of $12\, km/h$. $A$ minute later,the dog perceives her and gives chase at a speed of $16\, km/h$. How much distance is covered by the hare after being spotted? (in $m$)

What is the length of the bridge (in $m$) that a man riding at $15 \, km/h$ can cross in $5 \, minutes$?

$A$ train is travelling at a rate of $45 \, km/hr$. How many seconds will it take to cover a distance of $\frac{4}{5} \, km$?