Question

Two trains are 2 km apart and their lengths are 200 m and 300 m. They are approaching towards each other with a speed of 20 m/s and 30 m/s respectively. After how much time will they cross each other.

(a) 50 seconds 

(b) 100 seconds 

(c) \(\frac{25}{3}\) seconds 

(d) 150 seconds

Answer 1

(a) 50 seconds

Relative speed of the trains = (20 + 30) m/s = 50 m/s 

Total distance covered = (2 × 1000 + 200 + 300) m = 2500 m 

∴ The two trains will cross each other after \(\frac{2500}{50}\) seconds = 50 seconds.