$A$ person crosses a $600\, m$ long street in $5\, minutes$. What is his speed in $km/hr$?

Train $A$ crosses a stationary Train $B$ in $50 \,s$ and a pole in $20 \,s$ with the same speed. The length of Train $A$ is $240 \,m$. What is the length of the stationary Train $B$ (in $m$)?

Two trains,$130 \,m$ and $110 \,m$ long,are moving in the same direction. The faster train takes $1 \,minute$ to pass the other completely. If they are moving in opposite directions,they pass each other completely in $3 \,seconds$. Find the speed of each train (in $m/s$).

Two trains started at the same time,one from $A$ to $B$ and the other from $B$ to $A$. If they arrived at $B$ and $A$ respectively $4 \ hours$ and $9 \ hours$ after they passed each other,the ratio of the speeds of the two trains was:

Two men $A$ and $B$ walk from $P$ to $Q$ at a distance of $21 \text{ km}$ at speeds of $3 \text{ km/h}$ and $4 \text{ km/h}$ respectively. $B$ reaches $Q$ and returns immediately and meets $A$ at $R$. The distance from $P$ to $R$ is (in $\text{km}$):

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