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标题: gwd-11套数学有问题求帮忙？ [打印本页]

作者: andy2534 时间: 2017-4-13 17:15
标题: gwd-11套数学有问题求帮忙？
有2 道题有问题求各路大神帮忙。

Q11:

A certain company that sells only cars and trucksreported that revenues from car sales in 1997 were down 11 percent from 1996and revenues from truck sales in 1997 were up 7 percent from 1996. If total revenues from car sales and trucksales in 1997 were up 1 percent from 1996, what is the ratio of revenue fromcar sales in 1996 to revenue from truck sales in 1996?

A. 1 : 2

B. 4 : 5

C. 1 : 1

D. 3 : 2

E. 5 : 3

Q23:

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

(1) y > 0.15

(2) C ≥ 7.30

作者: Sean_PS 时间: 2017-4-13 21:18
A 0.89x+1.07y=1.01x+1.01y, 得x/y=1/2
B 隐藏条件x+y=1得C=8.5-2x

作者: andy2534 时间: 2017-4-14 15:37

Sean_PS 发表于 2017-4-13 21:18
A 0.89x+1.07y=1.01x+1.01y, 得x/y=1/2
B 隐藏条件x+y=1得C=8.5-2x

谢谢！看明白了！

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