Two trains travel in the same direction at 50 and 32 km/hr. A man in the slower train observes that it takes 15 seconds for the faster train to completely pass him. What is the length of the slower train?
- 75 meters
- 100 meters
- 160 meters
- 200 meters
- 250 meters
The Usual Method
Relative speed of the two trains = 50 – 32 = 18 km/hr.
18 km/hr = = 5 m/s
Hence, length of the slower train = 5 x 15 = 75 meters
Estimated Time to arrive at the answer = 30 seconds.
Since Distance = speed x time,
The length of the train should be a multiple of both the speed and the time.
Time taken is known as 15 seconds. Hence, length of the slower train should be a multiple of 15. The only option which is a multiple of 15 is option ‘1’.
Estimated Time to arrive at the answer = 5 seconds.