A train ,125 meters long travels at a speed of 45 km/hr crosses a bridge in 30 seconds. The length of the bridge is  Choose the correct choice from the following answers
A) 250 m  B) 245 m  C) 235 m  D) 220 m  E) 240 m

Rationale: "explanation : assume the length of the bridge = x meter total distance covered = 125 + x meter total time taken = 30 s speed = total distance covered / total time taken = ( 125 + x ) / 30 m / s = > 45 ã — ( 10 / 36 ) = ( 125 + x ) / 30 = > 45 ã — 10 ã — 30 / 36 = 125 + x = > 45 ã — 10 ã — 10 / 12 = 125 + x = > 15 ã — 10 ã — 10 / 4 = 125 + x = > 15 ã — 25 = 125 + x = 375 = > x = 375 - 125 = 250 answer : option a"
Answer: A