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). n is not divisible by 2 2). n is not divisible by 3 Please explain?

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). n is not divisible by 2 So n is an odd number n=1 - 0 n=3 - 8 n=5 - 0 INSUF ( I did not catch the n=3 case before ) 2). n is not divisible by 3 n=1 - 0 n=2 - 3 Insuf Together we know that n can not be 3 and n will be an ODD number 1, 5, 7, 11 and for all of these number the remainder will be 0 Choose C

Logitech could you please explain me about this ?? 1). n is not divisible by 2 So n is an odd number n=1 - 0 n=3 - 0 n=5 - 0 So We will always get 0 as a remainder SUF How is this sufficient ??

yalanand wrote:Logitech could you please explain me about this ?? 1). n is not divisible by 2 So n is an odd number n=1 - 0 n=3 - 0 n=5 - 0 So We will always get 0 as a remainder SUF How is this sufficient ?? 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? So we are asked to find the remainder. And in the first statement we all have 0 as the remainder when the number is divided by 24. For example n=5 (n-1)(n+1) = 4x6=24 divided by 24 , remainder is 0 Now looking at my previous post, I realized that the only ODD number that will leave a different remainder is n=3 2x4=8 and when is divided by 24 , the remainder is 8 So it seems like A can not be sufficient because of the n=3 case. Let's say what other will have to say :roll: