厚着脸皮，又来了~~

麦兜woo

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

答案选B，根据条件2得出6.5x + 8.5y≥ 7.30 ，怎么就可推出X是否小于0.8呢？

suomiliisa

根据2可以得出：6.5x + 8.5y≥ 7.30和x+y=1, 因为C的价钱是1KG的价钱。