Two trains of length 100 meters and 200 meters are 660 meters apart. They are moving towards each other on parallel tracks, at speeds of 90 km/h and 108 km/h. After how many seconds will the trains meet?  Choose the correct option.
A) 12 B) 14 C) 16 D) 18 E) 20

Rationale: "the speeds are 90000 / 3600 = 25 m / s and 108000 / 3600 = 30 m / s the relative speed is 55 m / s . time = 660 / 55 = 12 seconds the answer is a ."
Answer: A