Walking at the rate of $4 \, km/h$, a man covers a certain distance in $2 \, \text{hours} \, 45 \, \text{minutes}$. Running at a speed of $16.5 \, km/h$, the man will cover the same distance in how many minutes?

Two boys jointly begin to write a booklet containing $817$ lines. The first boy starts with the first line and writes $200$ lines an hour. The second boy starts with the last line,then writes line $816$ and so on,proceeding backwards at the rate of $150$ lines an hour. They will meet on:

It takes $24 \, s$ for a train travelling at $93 \, km/h$ to cross entirely another train half its length travelling in the opposite direction at $51 \, km/h$. It passes a bridge in $66 \, s$. What is the length of the bridge in meters?

$A$ boy started from his house by bicycle at $10:00 \, am$ at a speed of $12 \, km/h$. His elder brother started after $1 \, hour \, 15 \, minutes$ by scooter along the same path and caught him at $1:30 \, pm$. The speed of the scooter was (in $km/h$):

$A$ $180\, m$ long train crosses another $270\, m$ long train running in the opposite direction in $10.8\, seconds$. If the speed of the first train is $60\, km/h$, what is the speed of the second train in $km/h$?

Rajesh covers a certain distance by bus at $16 \text{ km/h}$ and returns to the starting point on a cycle at $9 \text{ km/h}$. His average speed for the whole journey is (in $\text{km/h}$):