Correct Answer - Option 1 : 130 m

**Given:**

Length of 1st train is 220m

Speed of 1st train is 110 km/h

Speed of 2nd train is 70 km/h

**Formula Used:**

Relative speed of train in opposite direction = S1 + S2

Time = Distance/Speed

**Calculation:**

Let the length of 2nd train be x

Relative speed of train = 110 + 70 = 180 × 5/18 = 50 m/sec

According to the question;

Time = (220 + x)/50

⇒ 7 = (220 + x)/50

⇒ 350 = 220 + x

⇒ x = 130 m

**∴ The length of other train is 130 m**