$A$ moving train crosses a man standing on a platform and a bridge of $300 \, \text{metres}$ long in $10 \, \text{seconds}$ and $25 \, \text{seconds}$ respectively. What will be the time taken by the train to cross a platform $200 \, \text{metres}$ long? (in $\text{seconds}$)

$A$ man starts from a place $P$ and reaches the place $Q$ in $7 \, hours$. He travels $\frac{1}{4}^{th}$ of the distance at $10 \, km/h$ and the remaining distance at $12 \, km/h$. The distance,in $km$,between $P$ and $Q$ is

Two trains,Kanpur Mail and Delhi Mail,start at the same time from stations Kanpur and Delhi respectively towards each other. After passing each other,they take $12\, \text{hours}$ and $3\, \text{hours}$ to reach Delhi and Kanpur respectively. If the Kanpur Mail is moving at the speed of $48\, \text{km/hr}$,the speed of the Delhi Mail is (in $\text{km/hr}$):

$A$ train $100 \, m$ long takes $3 \frac{3}{5} \, s$ to cross a man walking at the rate of $6 \, km/h$ in a direction opposite to that of the train. Find the speed of the train in $km/h$.

Aditya is travelling on his cycle and has calculated that he will reach point $A$ at $2\, pm$, if he travels at $10\, km/h$. He will reach there at $12\, noon$, if he travels at $15\, km/h$. At what speed must he travel to reach $A$ at $1\, pm$? (in $km/h$)

By walking at $\frac{3}{4}$ of his usual speed,a man reaches his office $20 \text{ minutes}$ later than usual. His usual time is (in $\text{minutes}$):