How long does a train 105 m long running at the speed of 68 km/hr takes to cross a bridge 90 m length? Choose the correct option:  A) 13.9 sec  B) 10.7 sec  C) 17.9 sec  D) 61.9 sec  E) 47.98 sec

Rationale: "speed = 68 * 5 / 18 = 19 m / sec total distance covered = 105 + 90 = 205 m . required time = 205 / 19 = 10.7 sec . answer : b"
Answer: B