A 900 m long train crosses a platform in 39 sec while it crosses a signal pole in 18 sec. What is the length of the platform?	Pick one:	A) 1000	B) 1050	C) 1060	D) 370	E) 380

Rationale: "speed = 900 / 18 = 50 / 1 m / sec . let the length of the platform be x meters . then , ( x + 300 ) / 39 = 50 / 1 = > x = 1950 m . l = 1950 - 900 = 1050 answer : option b"
Answer: B