Two trains 200m and 160m long run at the speed of 68kmph and 40kmph in opposite directions in parallel tracks. The time which they take to cross each other is?	Choose the correct choice from the following answers:
A) 5.6 sec	B) 8.9 sec	C) 10.8 sec	D) 12 sec	E) 15 sec

Rationale: "relative speed = 68 + 40 = 108 kmph * 5 / 18 = 30 m / s distance covered in crossing each other = 200 + 160 = 360 m required time = 360 * 1 / 30 = 12 sec answer is d"
Answer: D