gwd一题，明天考试请大家指教

zimerman

1kilo of a coffen blend consists of x kilo typeI coofee and y kilo type II.

the cost of the blend is C dollar per kilo C=6.5X+8.5y

is x<0.8

(1)   y > 0.15
(2)   C ≥ 7.30

zimerman

sorry 发错版了！