A 300 meter long train crosses a platform in 30 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform? Choose the correct choice
A) 227 B) 266 C) 230 D) 288 E) 200

Rationale: "speed = [ 300 / 18 ] m / sec = 50 / 3 m / sec . let the length of the platform be x meters . then , x + 300 / 30 = 50 / 3 3 ( x + 300 ) = 1500 è x = 200 m . answer : e"
Answer: E