A train ,135 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) 270 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 = 135 + x meter total time taken = 30 s speed = total distance covered / total time taken = ( 135 + x ) / 30 m / s = > 45 ã — ( 10 / 36 ) = ( 135 + x ) / 30 = > 45 ã — 10 ã — 30 / 36 = 135 + x = > 45 ã — 10 ã — 10 / 12 = 135 + x = > 15 ã — 10 ã — 10 / 4 = 135 + x = > 15 ã — 25 = 135 + x = 375 = > x = 375 - 135 = 240 answer : option e"
Answer: E