remainder

[gmatmachoman]

If n is a positive integer and r is the remainder when (n-1) (n+1) divided by 24, what is the value of r??

statement 1.

2 is NOT a factor of n

statement 2

3 is NOT a factor on n

[fibbonnaci]

This question has been exhaustively discussed in the forum.
Find the link here: https://www.beatthegmat.com/gmat-prep-re ... 16996.html

[gmatmachoman]

This question has been exhaustively discussed in the forum.
Find the link here: https://www.beatthegmat.com/gmat-prep-re ... 16996.html

thx for tat!

The best way of answering would have been is: when 2 & 3 are not factors of a Number, then that number is certainly a PRIME number..

Agreed??

let us try soem cases
n = 5

so n^2 -1= 24; which is divisible by 24 & remainder is 0

n =7
and again we have n^2 -1= 48 which is nicely divided by 24 & r= 0.

The answer posted by Ian is Logical.But lengthy.So i was looking for some classy answer based on prime numbers!!

But, yes Thx for ur answer Jo.

OA: C