The distance between places $A$ and $B$ is $999 \, km$. An express train leaves place $A$ at $6 \, am$ and runs at a speed of $55.5 \, km/h$. The train stops on the way for $1 \, hr \, 20 \, min$. It reaches $B$ at?

$A$ $150 \, m$ long train takes $10 \, s$ to pass over another $100 \, m$ long train coming from the opposite direction. If the speed of the first train is $30 \, km/h$,the speed of the second train is (in $km/h$):

Two trains start at the same time from Delhi and Mumbai and move towards each other at the rate of $85 \, km/h$ and $65 \, km/h$ respectively. When they meet,it is found that one train has travelled $20 \, km$ more than the other. Find the distance between Delhi and Mumbai (in $km$).

Two trains,one $160 \, m$ and the other $140 \, m$ long,are running in opposite directions on parallel tracks. The first is moving at $77 \, km/h$ and the other at $67 \, km/h$. How long will they take to cross each other? (in $seconds$)

Two persons begin together to write out a booklet containing $8190$ lines. The first person starts with the first line,writing at the rate of $200$ lines an hour; and the second person starts with the last line,then writes the $8189^{th}$ line and so on,proceeding backward at the rate of $150$ lines an hour. At what time will they meet (in $.4$)? (in hours)

$A$ and $B$ are $20 \text{ km}$ apart. $A$ can walk at an average speed of $4 \text{ km/hr}$ and $B$ at $6 \text{ km/hr}$. If they start walking towards each other at $7 \text{ a.m.}$,when will they meet? (in $\text{a.m.}$)