Two trains 120 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time which they take to cross each other is?  Choices.
A) 10.9
B) 10.7
C) 10.3
D) 10.08
E) 10.2

Rationale: relative speed = 60 + 40 = 100 km / hr . = 100 * 5 / 18 = 250 / 9 m / sec . distance covered in crossing each other = 120 + 160 = 280 m . required time = 280 * 9 / 250 = 252 / 25 = 10.08 sec . ' answer : d
Answer: D