oddyuibe

Hi,
the numbers for AWA part are based on a book about AWA written by Sun Yuan, a teacher in New Oriental School. The book has a green cover (the new version has a red cover).

I don't know whether you can get the AWA topic numbers from that book on the net. you can check the download center of Topway.com.

Good luck~

gocanucks

Question about #47.

47．用C.I.R.L.E 五个字母组成六个字母的词，C和C之间必须隔开，多少种？
[确认]：5P(6,6)-P(5,5)
[思路]：先不考虑C和C相邻的情况，按照六个位置进行全排列为5P(6,6)
再减去两个C相邻的情况，在这种情况下，把两个C看成一个元素，有P(5,5)中情况，所以答案是5P(6,6)-P(5,5)

I understand the part of P(5,5), but what about 5P(6,6)? I know 5 is for picking the extra one out of 5 characters. But is P(6,6) right? Since there are two same characters, we might be counting a same permutation twice.

Or look at it this way, P(6,6) means we have 6 choices for position 1, 5 for pos 2, etc. But since we have two same characters, we really have only 5 choices for position 1.

gocanucks

48．ds 以速度p1完成路程s1所需时间比以速度p2完成路程s2所需时间长？
(1)p1比p2大30
(2)s1比s2大30
[确认]：C
[思路]：以速度p1完成路程s1所需时间:S1/P1=(S2+30)/(P2+30); 以速度p2完成路程s2所需时间:S2/P2
真分数分子分母同加上相等的数，分数的值越来越大。假分数相反。所以，可以判断。

How do you know S2/P2 is 真分数?
s2=10, p2= 30 => s2/p2 < s1/p1
s2=60, p2=30 => s2/p2 > s1/p1
should be E instead.

feny

agree!! 48 should be E

falcon

23）.X+Y=77, XY=?
(1).X=Y+1
(2).X和Y有相同的十位数.
[确认]：D
[思路]：条件1可以通过解方程组求出X和Y,
           根据条件2，X和Y一个是38，一个是39，所以XY也是能确定的

我觉得该题有问题，题目并没有说明X,Y都是整数，所以我觉得应该选A

nz20000

i have different opinion on No.1, 39,  48

for No.1. presumbaly there are 200 people, so you can conclude that there is 100 sales, 7 salesmen and total 50 men. also if the number is 100, you can get 50 sales, 7 salesmen, and total 24 men. so you answer might be e other than a.

for 39, when the size is 1005 square feet, a is cheaper, but when the size is 1999, b is cheaper. so the answer should be e.

for 48, because 真分数 and 假分数 are all possible, 所以，can not判断。

zeus99

这题数字有问题吧？
13. 一社区有45户, 订报纸, 有 R, S, T 三种报,给出了三种报的订户人数分别是, S1=28, S2=17, S3=12,then, subscribe, both R&S, b1=9, both S&T b2=8, both R&T b3=7; Now 给出了一个重要条件, 订了三种的和什么都没有订的人,一样. 然后说, at least subscribe one kind of newspaper,29.
问: Subscribe only one kind Newspaper 的人数 X=?
[讨论]：X=S1+S2+S3-2B1-2B2-2B3+3a, 其中a是三种报纸都订了的户数 a=45-29=16

如果三种都定了的是16，那“both R&S, b1=9, both S&T b2=8, both R&T b3=7”，这句就不成立。
而从题目给的条件看（除了那句：at least subscribe one kind of newspaper,29.），a应该是6（而不是16），因此，至少定了一种的应该是39。对吗？

zeus99

24． X^2 + 1/(X^2) = 1 X^4 + 1/(X^4) = ? [确认]：-1 这个没懂，x^4>0, 1/(x^4), 为什么和<0， 是不是1？ 35．一个等边三角形在坐标轴上关于Y轴对称（有图），问知否顶点坐标？ 1. 底边的一个顶点 2. ·！%￥#… 选A [讨论]：condition 1 is sufficient, 这题，如果知道了一个底边的顶点，在Y 轴上的顶点可以有两个，所以应该不足以确定。 对吗？

smart

X^2 + 1/(X^2) = 1  X^4 + 1/(X^4) = ?
[确认]：-1

我认为解题思路是：[X^2 + 1/(X^2)]^2=1^2 解出 X^4 + 1/(X^4)+2=1

得出 X^4 + 1/(X^4)=-1

不过zeus99说的也很有道理，我也很郁闷，想不明白。。

smart

等边三角形在坐标轴上关于Y轴对称。

怎么会有两个顶点在Y轴上呢？