Question

The distance between two stations is $482km$. Two trains starts simultaneously from these stations on parallel track to cross each other. The speed of one of them is greater than that of the other by $4km/hr$. If the distance between the two trains after $3$ hours is $20km$, find the speed of ach train.

Answer 1

Let speed of first train $=xkm/hr$

Then speed of other train $=(x+4)km/hr$

Distance traveled by first train after $3hrs=3xkm$

Distance traveled by other train after $3hrs=3(x+4)km=(3x+12)km$

Now, distance between them is $20km$

So, $3x+(3x+12)+20=482$

$\Rightarrow$ $6x+32=482$

$\Rightarrow$ $6x=482-32$

$\Rightarrow$ $6x=450$

$\therefore$ $x=\frac{450}{6}=75km/hr$

$\therefore$ $x+4=75+4=79km/hr$

$\therefore$ Speed of the trains are $75km/hr$ and $79km/hr$