A train speeds past a pole in 15 seconds and a platform 100 m long in 40 seconds. Its length is? Choose the correct choice from the following answers
A) 188 m	B) 876 m	C) 251 m	D) 100 m	E) 145 m

Rationale: "let the length of the train be x meters and its speed be y m / sec . they , x / y = 15 = > y = x / 15 x + 100 / 40 = x / 15 x = 100 m . answer : d"
Answer: D