Correct Answer - Option 1 : 11/3 m/s

**Given:**

Speed of train = 72 kmph

**Formula used:**

Speed = Distance/Time

Relative speed = S_{1} – S_{2} (S_{1}, S_{2} are speed, S_{1} > S_{2})

**Calculation:**

Speed of train = 72kmph = 72 × 5/18 = 20 m/s

Let Length of the platform be A m.

According to the question,

(A + 260)/20 = 25.5

⇒ A = 250 m

Let the speed of passenger train be M m/s.

⇒ (240 + 250)/30 = M

⇒ M = 49/3 m/s

∴ Relative speed of two trains = 20 – 49/3 = 11/3 m/s