A boat goes 100 km downstream in 10 hours, and 200 Km upstream in 25 hours. The speed of the stream is?  Choose the correct answer:
A) 1 B) 22 1 / 7 C) 2 D) 22 1 / 2 E) 3

Rationale: "100 - - - 10 ds = 10 ? - - - - 1 200 - - - - 30 us = 8 ? - - - - - 1 s = ( 10 - 8 ) / 2 = 1 kmph . answer : a"
Answer: A