A train is 360 meter long is running at a speed of 45 km/hour. In what time will it pass a bridge of 140 meter length  Choose the correct option:
A) 20 seconds
B) 30 seconds
C) 40 seconds
D) 50 seconds
E) none of these

Rationale: "explanation : speed = 45 km / hr = 45 * ( 5 / 18 ) m / sec = 25 / 2 m / sec total distance = 360 + 140 = 500 meter time = distance / speed = 500 ∗ 2 / 25 = 40 seconds option c"
Answer: C