Two trucks each 250m long are running in opposite directions on parallel paths. Their speeds are 30 km/hr and 20 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one?	Select.
A) 77 sec  B) 66 sec  C) 48 sec  D) 55 sec  E) 36 sec

Rationale: relative speed = 20 + 30 = 50 km / hr . 50 * 5 / 18 = 125 / 9 m / sec . distance covered = 250 + 250 = 500 m . required time = 500 * 9 / 125 = 36 sec . answer : e
Answer: E