Two trains of equal lengths take 13 seconds and 26 seconds, respectively, to cross a pole. If these trains are moving in the same direction, then how long will they take to cross each other?

Question

Question

This question was previously asked in

SSC GD Constable (2022) Official Paper (Held On : 23 Jan 2023 Shift 3)

Answer 1

Given:

Train A takes 13 seconds to cross a pole.

Train B takes 26 seconds to cross a pole.

Concept:

Speed = Distance / Time

When two trains are moving in the same direction, their relative speed is the difference of their speeds.

Solution:

Let the length of each train be L.

⇒ Speed of train A = L/13, speed of train B = L/26.

When the two trains cross each other, the total distance covered is 2L (length of train A + length of train B).

Relative speed of the two trains = speed of train A - speed of train B = L/13 - L/26 = L/26.

Time taken to cross each other = total distance / relative speed = 2L / (L/26) = 52 seconds.

Hence, the two trains take 52 seconds to cross each other.