Two trains, one from Howrah to Patna and the other from Patna to Howrah, start simultaneously. After they meet, the trains reach their destinations after $9 \; \text{hours}$ and $16 \; \text{hours}$ respectively. The ratio of their speeds is

Two trains of equal lengths take $10 \; s$ and $15 \; s$ respectively to cross a telegraph post. If the length of each train is $120 \; m$,in what time (in $s$) will they cross each other when travelling in opposite directions?

$A$ train is moving at a speed of $120 \; km/hr$. If the length of the train is $120 \; m$,how long will it take to cross a railway platform $130 \; m$ long (in $sec$)?

$A$ train $75 \; m$ long overtook a person who was walking at the rate of $6 \; km/h$ and passed him in $7 \frac{1}{2}$ seconds. Subsequently,it overtook a second person,and passed him in $6 \frac{3}{4}$ seconds. At what rate (in $km/h$) was the second person travelling?

$A$ train $280 \; m$ long, running with a speed of $63 \; km/hr$, will pass a tree in (in $sec$):

$A$ train $240 \; m$ long passed a pole in $24 \; s$. How long (in $s$) will it take to pass a platform $650 \; m$ long?