The ratio of the speeds of a car,a train,and a bus is $5:9:4$. The average speed of the car,the bus,and the train together is $72 \text{ km/h}$. What is the average speed of the car and the train together? (in $\text{km/h}$)

If a distance of $50\, m$ is covered in $1\, minute$,$90\, m$ in $2\, minutes$,and $130\, m$ in $3\, minutes$,find the total distance covered in $15\, minutes$ (in $m$).

$A$ $75 \, m$ long train is moving at $20 \, km/h$. It will cross a man standing on the platform in (in $sec$):

$A$ train leaves the station $1 \, hr$ before the scheduled time. The driver decreases its speed by $4 \, km/hr$. At the next station $120 \, km$ away,the train reaches on time. Find the original speed of the train in $km/hr$.

$A$ passenger train $150 \ m$ long is travelling with a speed of $36 \ km/h$. If a man is cycling in the direction of the train at $9 \ km/h$,then the time taken by the train to pass the man is? (in $s$)

$A$ thief is stopped by a policeman from a distance of $150\, m$. When the policeman starts the chase,the thief also starts running. Assuming the speed of the thief as $7\, km/h$ and that of the policeman as $9\, km/h$,how far would the thief have run before he is overtaken by the policeman? (in $m$)