The length of the bridge, which a train 100 metres long and travelling at 45 km/hr can cross in 30 seconds, is?	Pick one:
A) 10 m
B) 16 m
C) 275 m
D) 19 m
E) 27 m

Rationale: "speed = [ 45 x 5 / 18 ] m / sec = [ 25 / 2 ] m / sec time = 30 sec let the length of bridge be x metres . then , ( 100 + x ) / 30 = 25 / 2 = > 2 ( 100 + x ) = 750 = > x = 275 m . answer : c"
Answer: C