Two trains of equal are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 27 sec. The length of each train is?  Select the correct option:
A) 50
B) 37.5
C) 27
D) 28
E) 21

Rationale: let the length of each train be x m . then , distance covered = 2 x m . relative speed = 46 - 36 = 10 km / hr . = 10 * 5 / 18 = 25 / 9 m / sec . 2 x / 27 = 25 / 9 = > x = 37.5 . answer : b
Answer: B