How long does a train 120 m long running at the speed of 70 km/hr takes to cross a bridge 150 m length?  Pick:
A) 12.7 sec B) 13.9 sec C) 18.1 sec D) 17.1 sec E) 19.7 sec

Rationale: "speed = 70 * 5 / 18 = 19.4 m / sec total distance covered = 120 + 150 = 270 m . required time = 270 / 19.4 ' = 13.9 sec . answer : b"
Answer: B