GWD数学部分 第四套Q15

chenglu9066

If n is a positive integer and r is the remainder when (n – 1)(n + 1) is divided by 24, what is the value of r?
(1)2 is not a factor of n.
(2)3 is not a factor of n.

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.

为啥选C啊 A不行吗

chenglu9066

hs1988520

你做题的思路是什么？怎么会选a呢 如果n=9 n=7算出来的结果不就不一样了吗

chenglu9066

是啊 我刚才 按照你说的再做了下
《1》N=3 或者9时  R=8     N=13  R=1 不能唯一确定R值
结合 1、2条件才可确定。
没有细心的算完