Correct Answer - Option 1 : 245 metre

**Given:**

Speed \(=\left(45 \times \dfrac{5}{18}\right)\) m/sec \(=\left(\dfrac{25}{2}\right)\) m/sec

Time = 30 sec.

**Formula Used:**

** **Distance = Speed × Time

**Calculation:**

Let the length of bridge be *x* metres.

\(\dfrac{10+x}{30}=\dfrac{25}{2}\)

⇒ 2(130 + *x*) = 750

⇒ *x* = 245 m.

**Conclusion:**

**Length of bridge will be 245 metres**