Why ~~~!!!!!!

manmuma

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 NOTsufficient.

Answer: E-C

helenhan777

试验几个数字就知道了，连立得结，是0！

manmuma

helenhan777 发表于 2013-9-16 08:08
试验几个数字就知道了，连立得结，是0！

I illustrated 5 and 7, and got different the result of r~~~~

helenhan777

0--0
1--0
2--3
3--8
4--15
5--0
6--12
7--0

manmuma

helenhan777 发表于 2013-9-16 11:58
0--0
1--0
2--3

咦~~~多谢大牛   我再好好算算~~~