作者yhubi (yhubill)
看板GMAT
标题[问题] PP 计量x3
时间Tue Apr 1 20:41:58 2008
142. 这提句意看不太懂 列式就列不出来 @@
The rate of a certain chemical reaction is directly proportional to the square
of the concentration of chemical A present and inversely proportional to the
concentration of chemical B present.
If the concentration of chemical B is increased by 100 percent,
which of the following is closest to the percent change in the concentration
of chemical A required to keep the reaction rate unchanged?
(A) 100% decrease
(B) 50% decrease
(C) 40% decrease
(D) 40% increase
(E) 50% increase
48.
A certain city with a population of 132,000 is to be divided into 11 voting
districts, and no district is to have a population that is more than 10 percent
greater than the population of any other district.
What is the minimum possible population that the least populated district could
have?
(A) 10,700
(B) 10,800
(C) 10,900
(D) 11,000
(E) 11,100
这堤我这样解:
132000/11=12000
(12000+x)-(12000-x) <= 10%(12000-x)
最多人之区人数-最少人之区人数 小於等於罪少人之区人数的10%
算出x 之後再算12000-x
还是另有其他算法呢??
7. 这题有爬文看之前的文章 还是看不太懂 ((product是积吗?? 还是我会错意))
For every positive even integer n, the function h(n) is defined to be the
product of all the even integers from 2 to n, inclusive.
If p is the smallest prime factor of h(100) + 1, then p is
(A) between 2 and 10
(B) between 10 and 20
(C) between 20 and 30
(D) between 30 and 40
(E) greater than 40
答案
D D E
感谢分享 计算过程
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※ 编辑: yhubi 来自: 61.217.110.48 (04/01 20:42)
※ 编辑: yhubi 来自: 61.217.110.48 (04/01 20:42)
1F：推 cmchen40:反应速率与A浓度的平方成正比，与B浓度的一次方成反比 04/01 22:34
2F：推 cmchen40:反应速率~{[A]^2}/[B] 当[B]增加100% 则[A]需增加(√2-1) 04/01 22:43
3F：→ cmchen40:所以 [A]大约需要增加40% 04/01 22:44
4F：→ cmchen40:前提是固定是反应速率~忘记打这个条件 @@... 04/01 22:46
5F：→ yhubi:原来是正比反比 列式也了解了 感谢 04/01 22:51
6F：推 fly12404:第三题: 基本上2n+1不可能为2的倍数 04/01 23:13
7F：→ fly12404:3n+1不可能为三的倍数 04/01 23:14
8F：→ fly12404:题目为2x4x6x8...x98x100 也可以写成2的五十次方乘以 04/01 23:14
9F：→ fly12404:(1x2x3x4...x50) <----用之前的想法 即可得知最小质数因 04/01 23:15
10F：→ fly12404:子大於40 <--答案E 04/01 23:15
11F：→ yhubi:了解了 原来是用这个观念 很少遇到这种题目 感谢回答 04/01 23:32
12F：→ yhubi:也可以说最小质因数大於47罗 47*[(2^50)*(1*2*.没47..50)]+1 04/01 23:35