$A$ train $150 \, m$ long takes $20 \, s$ to cross a platform $450 \, m$ long. The speed of the train in $km/h$ is:

$A$ man on tour travels the first $160 \, km$ at $64 \, km/hr$ and the next $160 \, km$ at $80 \, km/hr$. What is the average speed for the first $320 \, km$ of the tour (in $km/hr$)?

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?

$A$ farmer travelled a distance of $61 \, km$ in $9 \, hrs$. He travelled partly on foot at the rate of $4 \, km/hr$ and partly on bicycle at the rate of $9 \, km/hr$. The distance travelled on foot is (in $km$):

$A$ carriage driving in a fog passed a man who was walking at the rate of $3 \text{ km/h}$ in the same direction. He could see the carriage for $4 \text{ minutes}$ and it was visible to him up to a distance of $100 \text{ m}$. What was the speed of the carriage in $\text{km/h}$?

$A$ man can reach a certain place in $30 \, \text{hours}$. If he reduces his speed by $\frac{1}{15}^{th}$, he goes $10 \, \text{km}$ less in that same time. Find his speed in $\text{km/hr}$.