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标题: 【prep数学讨论】请各位童鞋进来看看这道数学题 [打印本页]

作者: mes61 时间: 2010-9-18 16:44
标题: 【prep数学讨论】请各位童鞋进来看看这道数学题
a construction company was paid a total of $500,000 for a construction project. The company's only costs for the project were for labor and materials. was the company's profit for the project greater than $150,000?

1 the company's total cost was 3 times its cost for materials
2 the company's profit was greater than its cost for labor

作者: mes61 时间: 2010-9-18 16:48
没人理啊。。。

作者: ffffighting 时间: 2010-9-18 17:03
是两个一起sufficient么？居然忘了这个是不是C选项了...

作者: samalex 时间: 2010-9-18 17:19
我觉得选C,

profit + cost = 500,000
cost = labor + material
求 profit > 150,000 ?

1) cost = 3 material,
==> 2 material = labor ---------
但是, 无法得出 material 与 profit 的大小关系, 无法得知 profit > 150,000 ----------不充分
2) profit > labor,--------
因为 labor 与 material 的大小无法确定, 同样无法得知 profit > 150,000 ---------- 不充分

联立 1) 和2)
根据, 和
profit > 2 material
cost = 3 material
profit + cost = 500,000
假设 profit' 为最小值的 profit = 2 material 时,
profit' + cost = 500,000
material = 100,000
profit > profit' = 200,000
所以, C

作者: mes61 时间: 2010-9-18 18:14

谢谢

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