The length of the bridge, which a train 180 meters long and travelling at 45 km/hr can cross in 30 seconds, is?
Answers:
A) 195 m  B) 156 m  C) 245 m  D) 156 m  E) 156 m

Rationale: "speed = ( 45 * 5 / 18 ) m / sec = ( 25 / 2 ) m / sec . time = 30 sec . let the length of bridge be x meters . then , ( 180 + x ) / 30 = 25 / 2 = = > 2 ( 180 + x ) = 750 = = > x = 195 m . answer : a"
Answer: A