Ravi and Ajay start simultaneously from a place $A$ towards $B$,$60 \, km$ apart. Ravi's speed is $4 \, km/h$ less than that of Ajay. Ajay,after reaching $B$,turns back and meets Ravi at a place $12 \, km$ away from $B$. Ravi's speed is (in $km/h$):

Starting from his house,a student walks at a speed of $2.5 \, km/hr$ and reaches his school $6 \, minutes$ late. Next day he increases his speed by $1 \, km/hr$ and reaches the school $6 \, minutes$ early. How far is the school from his house? (in $km$)

Three men step off together from the same spot. Their steps measure $63 \, cm$,$70 \, cm$,and $77 \, cm$ respectively. The minimum distance each should cover so that all can cover the distance in complete steps is (in $cm$):

The distance between two stations,Delhi and Amritsar,is $450 \, km$. $A$ train starts at $4 \, p.m.$ from Delhi and moves towards Amritsar at an average speed of $60 \, km/hr$. Another train starts from Amritsar at $3:20 \, p.m.$ and moves towards Delhi at an average speed of $80 \, km/hr$. At what time will the two trains meet?

$A$ speed of $45\, km/h$ is equivalent to which speed in $m/s$?

$A$ thief is spotted by a policeman from a distance of $200 \text{ meters}$. When the policeman starts to chase the thief,the thief also starts running. Assuming the speed of the thief is $10 \text{ km/h}$ and that of the policeman is $12 \text{ km/h}$,how far will the thief have run before he is overtaken by the policeman? (in $\text{km}$)