$A$ student walks from his house at $5 \, km/h$ and reaches his school $10 \, minutes$ late. If his speed had been $6 \, km/h$,he would have reached $15 \, minutes$ early. The distance of his school from his house is (in $km$):

$A$ $320\, m$ long train moving at an average speed of $120\, km/h$ crosses a platform in $24\, seconds$. $A$ man crosses the same platform in $4\, minutes$. What is the speed of the man in $m/s$?

$A$ $280 \, m$ long train moving with an average speed of $108 \, km/h$ crosses a platform in $12 \, s$. $A$ man crosses the same platform in $10 \, s$. What is the speed of the man in $m/s$?

Two trains of lengths $120 \,m$ and $80 \,m$ are running in the same direction with velocities of $40 \,km/h$ and $50 \,km/h$ respectively. The time taken by them to cross each other is (in $sec$).

The distance between two stations,Delhi and Amritsar,is $450 \, km$. $A$ train starts at $4 \, p.m.$ from Delhi and moves towards Amritsar at an average speed of $60 \, km/hr$. Another train starts from Amritsar at $3:20 \, p.m.$ and moves towards Delhi at an average speed of $80 \, km/hr$. At what time will the two trains meet?

$A$ train $300 \text{ m}$ long is running at a speed of $90 \text{ km/h}$. How many seconds will it take to cross a $200 \text{ m}$ long train running in the opposite direction at a speed of $60 \text{ km/h}$?