$A$ $135\, m$ long train is running with a speed of $54\, km/h$. In what time will it pass a telegraph post? (in $seconds$)

$A$ 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 friends started for a place,one by motorcycle and the other by train. The speed of the motorcycle is $30 \, km/h$ and that of the train is $24 \, km/h$. The first one takes $6 \, hr \, 12 \, min$ to reach the destination. Find the time taken by the second one to reach the destination (in $hr$).

Rakesh sets out to cycle from Delhi to Mathura and at the same time Suresh starts from Mathura to Delhi. After passing each other,they complete their journeys in $9$ and $16 \, \text{hours}$,respectively. At what speed does Suresh cycle if Rakesh cycles at $16 \, \text{km/h}$?

$A$ train $300 \ m$ long is running with a speed of $54 \ km/h$. In what time will it cross a telephone pole? (in $seconds$)

$A$ boy takes as much time in running $12 \, m$ as a car takes in covering $36 \, m$. The ratio of the speeds of the boy and the car is