$A$ man with $\frac{3}{5}$ of his usual speed reaches the destination $2 \frac{1}{2}$ hours late. Find his usual time to reach the destination? (in $hours$)

$A$ train travelling with a speed of $60 \, km/h$ catches another train travelling in the same direction and then leaves it $120 \, m$ behind in $18 \, seconds$. The speed of the second train is (in $km/h$):

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 $m$).

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

Two trains,each of length $90\, m,$ run on parallel tracks. When running in the same direction,the faster train passes the slower train completely in $18\, s,$ but when they are running in opposite directions approaching each other at the same speeds as before,they cross each other in $9\, s.$ Find the speed of each train (in $m/s$).

Two places $P$ and $Q$ are $162 \, km$ apart. $A$ train leaves $P$ for $Q$ and simultaneously another train leaves $Q$ for $P$. They meet at the end of $6 \, hours$. If the former train travels $8 \, km/h$ faster than the other,then the speed of the train from $Q$ is (in $km/h$):