Robin in NC wrote:
A alone is sufficient.
4 + 7(3x-1) = 21x + 3. It will be always divisible by 3.
Second is clearly insuffiicent
Could you show step by step how you set that up? I have trouble with this type of problem.
From A, n + 1 is divisible by 3.
So n+1 = 3x. x is an unknown integer.
so n = 3x-1.
4 + 7 (3x -1) = 21x - 3.
Dividing it by 3
It reduces to 7x - 1 and you can see that there cant be any reminder when x is an integer.
Hope that helps.