Correct Answer - Option 4 : 705 m

**Given :**

Rajan sitting inside a train travelling at a speed of 108 km/h crosses another train running in the same direction in 47 seconds.

The speed of the slower train is 25 m/s and the length of the faster train is two times the length of the slower train.

**Formula used :**

Time = Distance/Speed

**Calculations :**

Let the length of the slower train be 'L' m

Speed of the faster train in m/s = 108 × (5/18) = 30 m/s

Speed of slower train = 25 m/s

According to the question

47 = (length of the slower train)/Relative speed

⇒ 47 = L/(30 - 25) (when train move in same direction relative speed is the difference of the speeds)

⇒ l = 47 × 5 = 235 m

Now length of faster train = 2 × L = 2L

⇒ 470 m

Total length of both the trains = 235 + 470 = 705 m

**∴ The length of both the trains will be 705 m**