Question

Two trains of equal lengths are running on parallel lines in the same direction at the rate of $46$ km/hr and $36$ km/hr. The faster train passes the slower train in $36$ seconds. What is the length of the trains ?

• A. $50$ m
• B. $72$ m
• C. $80$ m
• D. $82$ m

Answer 1

The correct option is A $50$ m

To cross each other, two trains have to cover a distance equal to the sum of the lengths of the train.

Let the length of the trains be $x$ m each.

So the distance to be covered $=2x$.

Now the trains are running int he same direction.

$\therefore$ Their relative speed=$(46-36)$km/hr.=10km/hr.=$10\times \frac{5}{18}$km/hr.=$\frac{25}{9}$m/sec.

So, the time taken by the trains to cove $2x$ m distance

=$2x÷\frac{25}{9}$sec.

$\therefore$ By the given conditions,

$2x÷\frac{25}{9}sec=36sec$.

Or $x=50m$.

So the length of each train $=50m$.