A train is moving in from north to south direction. It overtakes Raj and Madhur who are walking in the same direction at the rate of 2 km/h and 4 km/h in 9 sec and 10 sec, respectively. If the train is x metres long, find the value of x.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e 50.
Train speed = V km/h = (5V/18) m/s and Raj’s speed = 2 km/h = 5/9 m/s
Relative speed with Raj = (5V/18 − 5/9)
Time taken = 9 s
So, train length x = (5V/18 − 5/9) × 9 = (5V/2 − 5)
Madhur’s speed = 4 km/h = 10/9 m/s
Relative speed with Madhur = (5V/18 − 10/9)
Time taken = 10 s
So, train length x = (5V/18 − 10/9) × 10 = (25V − 100)/9
5V/2 − 5 = (25V − 100)/9
So V = 22 km/h Now, x = 5V/2 − 5 = 55 − 5 = 50