Train A, with a length of 300 meters, is going in the south direction

1.	Train A, with a length of 300 meters, is going in the south direction at a speed of 45 kilometers per hour. Train B, with a length of 240 meters, is going in the same direction at a speed of 60 kilometers per hour, 120 meters behind the rear end of train A. How long will Train B take to cross a person sitting exactly in the middle of Train A?1. 110 second2. 122.4 second3. 120.3 second4. 100.5 second
Answer» Correct Answer - Option 2 : 122.4 second Given: For Train A, Length = 300 meters Speed = 45 kilometers per hour. For train B, Length = 240 meters Speed = 60 kilometers per hour. Train B is 120 meters behind Train A. Formula Used: meter/second = (5/18) kilometer/hour Relative speed: When running in the same direction, Speed = (x – y) where x is the speed of the second train. y is the speed of the first train. Speed = Distance/Time Time = Distance/Speed Calculation: Man is sitting exactly in the middle of train A Distance that needs to be covered by B is, ⇒ Length of Train B + Distance between 2 trains + Distance of a sitting man ⇒ 240 + 120 + 150 ⇒ 510 meters Relative speed: ⇒ (60 – 45) ⇒ 15 km/hr. As the distance is in meters and Time in seconds We need to convert km/hr into m/sec ⇒ 5/18 × 15 ⇒ 25/6 meter/second Time = Distance/Speed ⇒ Time = 510/(25/6) ⇒ Time = (510 × 6)/25 ⇒ Time = 122.4 second ∴ Time taken by Train B to cross a man is 122.4 seconds.

Train A, with a length of 300 meters, is going in the south direction at a speed of 45 kilometers per hour. Train B, with a length of 240 meters, is going in the same direction at a speed of 60 kilometers per hour, 120 meters behind the rear end of train A. How long will Train B take to cross a person sitting exactly in the middle of Train A?1. 110 second2. 122.4 second3. 120.3 second4. 100.5 second

Answer» Correct Answer - Option 2 : 122.4 second

Given:

For Train A,

Length = 300 meters

Speed = 45 kilometers per hour.

For train B,

Length = 240 meters

Speed = 60 kilometers per hour.

Train B is 120 meters behind Train A.

Formula Used:

meter/second = (5/18) kilometer/hour

Relative speed:

When running in the same direction,

Speed = (x – y)

where

x is the speed of the second train.

y is the speed of the first train.

Speed = Distance/Time

Time = Distance/Speed

Calculation:

Man is sitting exactly in the middle of train A

Distance that needs to be covered by B is,

⇒ Length of Train B + Distance between 2 trains + Distance of a sitting man

⇒ 240 + 120 + 150

⇒ 510 meters

Relative speed:

⇒ (60 – 45)

⇒ 15 km/hr.

As the distance is in meters and Time in seconds

We need to convert km/hr into m/sec

⇒ 5/18 × 15

⇒ 25/6 meter/second

Time = Distance/Speed

⇒ Time = 510/(25/6)

⇒ Time = (510 × 6)/25

⇒ Time = 122.4 second

∴ Time taken by Train B to cross a man is 122.4 seconds.