A train is 510 meter long is running at a speed of 45 km/hour. In what time will it pass a bridge of 140 meter length?  Choices: A) 76 seconds B) 18 seconds C) 52 seconds D) 19 seconds E) 45 seconds

Rationale: "speed = 45 km / hr = 45 * ( 5 / 18 ) m / sec = 25 / 2 m / sec total distance = 510 + 140 = 650 meter time = distance / speed = 650 * ( 2 / 25 ) = 52 seconds answer : c"
Answer: C