国际顶尖MBA申请交流平台--TOPWAY MBA

标题: 求助一道DS题~~~~~~~~~~ [打印本页]

作者: oliviading 时间: 2007-9-1 14:43 标题: 求助一道DS题~~~~~~~~~~

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 ≥ 7.3

Answer: E-->B

可是,B根本就算不出x < 0.8是否满足的条件呀~~因为C可取无限大了,那么x既可以>0.8也可以<0.8都没有问题呀,,,不是么???

求助各位指点迷津~~

作者: susanyakis 时间: 2007-9-1 19:06

One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee

《=》x+y=1

作者: littlestoner 时间: 2007-9-2 06:56

x+y=1,so c=6.5x+8.5y=6.5x+8.5(1-x)=8.5-2x>=7.3

so x<=0.6

right?

作者: oliviading 时间: 2007-9-6 06:40

Oh~~~Yup...Thank you very much!!!

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