GWD26-31，好像答案不对。

One kilogram of a certain coffee blend
consists of x kilogram of type I coffee and y kilogram of type II coffee.  The cost of the blend is C dollars per kilogram,
where C = 6.5x + 8.5y.  Is x < 0.8?

(1)   y > 0.15

(2)
            C ≥ 7.30

A. Statement (1) ALONE is
sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is
sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER
are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is
sufficient.

E. Statements (1) and (2) TOGETHER
are NOT sufficient.

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=383992&page=1

昨天才在一个帖子里说了，楼主发帖前搜一搜啊~~