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in base 10 notation 是什么意思啊?

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11#
发表于 2010-4-26 14:52:38 | 只看该作者
第一题A
画6个格子,穷举法吧
1和6位子固定的,按第一排中间的格子开始讨论。只有5种
12#
发表于 2010-4-26 15:25:02 | 只看该作者
Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y.At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?
A.4
B.6
C.8
D.10
E.12

这题之前有一个帖子有说到简单的做法,但是貌似挺难想到的,我是用最一般的做法做的,所以步骤有点长。
你设y完成工作的天数是n,则x用n+2天,所以Y得效率是1/n,X的效率是1/n+2.
然后列出等式:5/4=Y的效率+x的效率
这样就可以算出n是4(去掉一个负数值)
然后用2除于1/n+2算出是12天。


Q35:
What is the median number of employees assigned per project for the projects at Company Z?
(1)25 percent of the projects at Company Z have 4 or more employees assigned to each project.
(2) 35 percent of the projects at Company Z have 2 or fewer employees assigned to each project.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

这个要靠理解了,最好画一个XX图(我都忘了叫什么名堂了),从2开始开口向左的有35%,从4开始向右开口的有25%,因为是“人”,所以中间必定是个“3”,所以,当50%时是落在3上边的,因此知道两个条件就可以求出。
13#
 楼主| 发表于 2010-4-26 19:35:40 | 只看该作者
流泪感激nn们的帮助,换题库例如也得拼一把!
14#
发表于 2010-4-26 19:38:10 | 只看该作者
X和y机器的那题列一下天他们速度*时间=w,联立,再加一条(共同速度)*3天=5/4w,就可以了。

下面那题:
25%>=4,35%<=2,所以剩40%在3,中位数就是3
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