Two trains of equal are running on parallel lines in the same direction at 52 km/hr and 36 km/hr. The faster train passes the slower train in 36 sec. The length of each train is? Choose the correct choice from the following options.
A) 50 m
B) 72 m
C) 80 m
D) 82 m
E) 84 m

Rationale: "let the length of each train be x m . then , distance covered = 2 x m . relative speed = 52 - 36 = 16 km / hr . = 16 * 5 / 18 = 40 / 9 m / sec . 2 x / 36 = 40 / 9 = > x = 80 . answer : c"
Answer: C