Can this be a wrong problem?

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Can this be a wrong problem?

by eustudent » Tue Jun 02, 2009 6:45 am
IF N is a positive integer and R is the reminder when (N-1)(N+1) is divided by 24, what is the value of R?

1) N is not divisible by 2
2) N is not divisible by 3

Right answer is C according to the gmat software. However, after using the 2 statements, we can plug values 7, 13, 19 and they will all satisfy the given answer. Since we have more than 1 possible solution(answer) to the problem, we cannot find the exact value of N and, therefore E should be the right answer.
Source: — Data Sufficiency |

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by aj5105 » Tue Jun 02, 2009 6:49 am
Check this post dude, everything is out here: https://www.beatthegmat.com/divisibility ... 23039.html

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by eustudent » Tue Jun 02, 2009 6:59 am
thank you sir!