两道GWD 27的数学题

Q33:

The table above shows the results of a survey of 100 voters each responded “favorable” or “unfavorable” or “not sure” when asked about their impressions of candidate M and of candidate N.  What was the number of voters who responded “favorable” for both candidates?

(1)   The number of voters who did not respond “favorable” for either candidate was 40.

(2)     The number of voters who responded “unfavorable” for both candidates was 10.

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.

Answer:  A

这个怎么算啊？一向集合题做不好。。。

Q34:

If n is a positive integer, what is the remainder when 3⁸ⁿ⁺³ + 2 is divided by 5?

A.     0

B.     1

C.     2

D.     3

E.      4

Answer: A

我怎么算都是E: 8n+3尾数是7， 7+2=9 余数4 是不是我哪里没对？

Q33:

第一个条件说40人没有偏好于任何一个候选人，也就是说有100-40=60人至少都偏好于一个候选人，

又知道两个集合的交集等于两个集合总相加后减去两个集合的合集，

于是40+30-60=10，就是同时偏好两人的人数。

第二个条件不充分，因为没有区分不偏好和不确定的人。

所以答案是A。的尾数

Q34：

 3⁸ⁿ⁺³ + 2=
            3⁸ⁿ ×3³+ 2

3⁸  的个位数是1，因为3的幂是每4倍次就同尾数循环的。

于是可得出尾数为1的乘以27，尾数是7，7+2=9，余数为4.

楼主其实是算对了，这个答案未必都对，自己没有错不要怀疑自己。

提供我第一题的思路，希望有所帮助。本人10.10考，共勉！