$A$ man standing on a railway platform observes that a train going in one direction takes $4 \,seconds$ to pass him. Another train of the same length going in the opposite direction takes $5 \,seconds$ to pass him. The time taken (in $seconds$) by the two trains to cross each other will be:

Seeta and Geeta cycled towards each other,one from point $A$ and the other from point $B$,respectively. Seeta left point $A$ $6 \, hours$ later than Geeta left point $B$,and it turned out on their meeting that Seeta had travelled $12 \, km$ less than Geeta. After their meeting,they kept cycling with the same speed,and Seeta arrived at $B$ $8 \, hours$ later and Geeta arrived at $A$ $9 \, hours$ later. Find the speed of the faster cyclist in $km/hr$.

Amit starts his journey from Patna to Delhi at a speed of $50 \, km/h$. The distance between Delhi and Patna is $1000 \, km$. He takes a rest of $20 \, minutes$ after every $3 \, hours$ of driving. How much total time will he take to reach Delhi? (in $hrs$)

$A$ train goes from Ballygunge to Sealdah at an average speed of $20 \text{ km/h}$ and comes back at an average speed of $30 \text{ km/h}$. The average speed of the train for the whole journey is (in $\text{km/h}$)

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 $sec$).

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