Two trains 140m and 160m long run at the speed of 60kmph and 48kmph in opposite directions in parallel tracks. The time which they take to cross each other is?
Choices
A) 5.6 sec
B) 8.9 sec
C) 10 sec
D) 12.6 sec
E) 15 sec

Rationale: "relative speed = 60 + 48 = 108 kmph * 5 / 18 = 30 m / s distance covered in crossing each other = 140 + 160 = 300 m required time = 300 * 1 / 30 = 10 sec answer is c"
Answer: C