Two men are standing on opposite ends of a bridge of $1200 \, m$ long. If they walk towards each other at the rate of $5 \, m/min$ and $10 \, m/min$ respectively,in how much time will they meet each other? (in $minutes$)

The average speed of a car is $1 \frac{4}{5}$ times the average speed of a bus. $A$ tractor covers $575 \text{ km}$ in $23 \text{ hours}$. How much distance will the car cover in $4 \text{ hours}$ if the speed of the bus is twice the speed of the tractor? (in $\text{km}$)

$A$ train takes $18 \, s$ to pass completely through a station $162 \, m$ long and $15 \, s$ through another station $120 \, m$ long. The length of the train (in $m$) is:

$50$ trees are standing in a line such that the distance between any two consecutive trees is the same. $A$ car takes $18 \, seconds$ to travel from the $13^{th}$ tree to the $34^{th}$ tree. How much time (in $seconds$) will it take to reach from the first tree to the $50^{th}$ tree?

$A$ train leaves station $A$ at $7 \, am$ and reaches station $B$ at $11 \, am$. Another train leaves station $B$ at $8 \, am$ and reaches station $A$ at $11.30 \, am$. At what time do the two trains cross each other?

$A$ man covers a certain distance by car driving at $70 \, km/hr$ and he returns to the starting point riding on a scooter at $55 \, km/hr$. Find his average speed for the whole journey in $km/hr$.