天山 9-16

天山9-16, the answer is C, but I think it is E, since the qustion ask the reminder r = ? when (n-1)*(n+1)/24, 1)2  is not a factor of n, 2) 3 is not factor of n, then condition 1+ 2, we try when 11, or 5, r=0, but when n=15, r=1, so, there are more than one value for r, then, I think the answer is E.

But it is open discussion, I am not good at math.

thanks for any further dicussion.

for your reference

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=84239&page=1

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=84324&page=1