Question

A train of length 200 m running at speed 90 km/hr crosses a tunnel in 24 seconds and another train running at speed 108 km/hr crosses the same tunnel in 30 seconds. Find the length of the second train.
1. 200 m
2. 400 m
3. 500 m
4. 550 m
5. 900 m

Answer 1

Correct Answer - Option 3 : 500 m

Given :

length of train 1 = 200 m

Speed of train 1 = 90 km/hr = 25 m/s

Speed of train 2 = 108 km/hr = 30 m/s

Calculations :

 Let the length of tunnel be x m and length of the second train be L_T

According to question first train takes 24 sec to pass the tunnel so,

⇒ (200 + x)/25 = 24

⇒ x  = 400 m

∵  it is given that train 2 passes the tunnel in 30 s

⇒ ( L_T + x )/30 = 30

⇒ (L_T + 400)/30 = 30

⇒ L_T = 500 m

∴ The length of the second train is 500 m.