Correct Answer - Option 3 : 11

**Given :**

Length of the train is 290 m

Length of bridge is 310 m

Time taken by train to cross the bridge is 24 seconds

**Formula used :**

Distance = Time × Speed

**Calculations :**

Total length to cross by train = length of train + length of bridge

⇒ 310 + 290 = 600 m

According to the question

Speed of train = 600/24

⇒ 25 m/s

Speed in km/h = 25 × (18/5)

⇒ 90 km/h

Now,

Time to cover 990 km by train = 990/90

⇒ 11 hours

∴ **The time taken to cover 990 km is 11 hours.**