Two men $A$ and $B$ start from a place $P$ walking at $3 \, km/h$ and $3.5 \, km/h$ respectively. How many $km$ will they be apart at the end of $3 \, h$,if they walk in opposite directions (in $.5$)?

If $I$ walk at $5\, km/hr$,$I$ miss a train by $7\, minutes$. However,if $I$ walk at $6\, km/hr$,$I$ reach the station $5\, minutes$ before the departure of the train. The distance between my house and the station is (in $km$)

$A$ boy goes to his school from his house at a speed of $3 \text{ km/hr}$. If he takes $5 \text{ hours}$ in total for going and coming back,the distance between his house and school is (in $\text{km}$):

$A$ bus takes $15\, hours$ to travel from Delhi to Chandigarh. The bus travels for one-third of the total time at a speed of $80\, km/h$. It travels for $40\%$ of the remaining time at a speed of $70\, km/h$. It travels for $\frac{2}{3}$ of the remaining time at a speed of $85\, km/h$,and the rest of the time at a speed of $100\, km/h$. What is the total distance covered by the bus?

Amit started cycling along the boundaries of a square field from corner point $A$. After half an hour,he reached the corner point $C$,diagonally opposite to $A$. If his speed was $8 \, km/h$,what is the area of the field in square $km$?

$A$ $300 \, m$ long train is travelling with a speed of $45 \, km/hr$ when it passes point $A$ completely. At the same time,a motorbike starts from point $A$ with a speed of $70 \, km/hr$. When it exactly reaches the middle point of the train,the train increases its speed to $60 \, km/hr$ and the motorbike reduces its speed to $65 \, km/hr$. How much distance will the motorbike travel while passing the train completely? (in $km$)