$A$ 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 $\text{a.m.}$)

$A$ train travels at a speed of $10\, m/s$ and leaves Trivandrum for Nagercoil at $8\, AM$. At what distance from Nagercoil will it meet a train which leaves Nagercoil for Trivandrum at $8.20\, AM$ and travels one-third faster than the former? The distance from Trivandrum to Nagercoil is $68\, km$. (in $km$)

$A$ $100\, m$ long train passes a bridge at the rate of $72\, km/h$ in $25\, s$. What is the length of the bridge (in $m$)?

Two trains $A$ and $B$ start at the same time from Delhi and Patna respectively towards each other. They meet after $16 \, h$. If the distance between Delhi and Patna is $1872 \, km$ and train $B$ runs $27 \, km/h$ faster than train $A$,what is the speed of train $A$ in $km/h$?

$A$ train crosses a pole in $10 \, s$ and a platform,which is $40 \%$ longer than the length of the train,in $24 \, s$. If the length of the platform is $140 \, m$,what is the speed of the train in $m/s$?

$A$ train $300 \ m$ long is running with a speed of $54 \ km/h$. In what time will it cross a telephone pole? (in $seconds$)