On a tour,a man travels at the rate of $64 \text{ km/h}$ for the first $160 \text{ km}$,then travels the next $160 \text{ km}$ at the rate of $80 \text{ km/h}$. The average speed in $\text{km/h}$ for the first $320 \text{ km}$ of the tour is:

One aeroplane started $30 \, \text{minutes}$ later than the scheduled time from a place $1500 \, \text{km}$ away from its destination. To reach the destination at the scheduled time,the pilot had to increase the speed by $250 \, \text{km/hr}$. What was the original speed of the aeroplane? (in $\text{km/hr}$)

Ramesh crosses a $600 \, m$ long street in $5 \, \text{minutes}$. His speed in $km/h$ is:

$A$ man leaves a point $P$ and reaches the point $Q$ in $4 \, hours$. Another man leaves the point $Q$,$2 \, hours$ earlier and reaches the point $P$ in $4 \, hours$. Find the time in which the first man meets the second man (in $hours$).

Without any stoppage, a person travels a certain distance at an average speed of $42 \, km/h$ and with stoppages he covers the same distance at an average speed of $28 \, km/h$. How many minutes per hour does he stop?

$A$ motorist covered the first $20 \text{ km}$ of his journey in $30 \text{ minutes}$ and the remaining $29 \text{ km}$ in $40 \text{ minutes}$. His average speed in $\text{km/hr}$ is: