A 300 m long train crosses a platform in 33 sec while it crosses a signal pole in 18 sec. What is the length of the platform?	Choose the correct answer.
A) 286 m  B) 250 m  C) 277 m  D) 278 m  E) 267 m

Rationale: "speed = 300 / 18 = 50 / 3 m / sec . let the length of the platform be x meters . then , ( x + 300 ) / 33 = 50 / 3 = > x = 250 m . answer : b"
Answer: B