A train 400 meters long completely crosses a 300 meters long bridge in 45 seconds. What is the speed of the train is?	Choose the correct choice from the following:
A) 32
B) 56
C) 29
D) 27
E) 21

Rationale: "s = ( 400 + 300 ) / 45 = 700 / 45 * 18 / 5 = 56 answer : b"
Answer: B