Two train each 500 m long, and running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.
Choose the correct answer
A) 20 sec  B) 25 sec  C) 24 sec  D) 30 sec  E) 22 sec

Rationale: speed = ( 45 + 30 ) = 75 * 5 / 18 = = > 125 / 6 req time = 500 * 6 / 125 = 24 sec answer c
Answer: C