1. The problem statement, all variables and given/known data[/b] See attached 2. Relevant equations See attached 3. The attempt at a solution I know the answer is 6 or zero... but I cant figure out how to "show" this. When typing this equation into my calculator, I can clearly see that the number always ends in .0 or .6. Initially I let k = (n-(n-1)) so the equation turns into (n-(n-1))*([n-(n-1)] +1) / n = n(n-1)/n (1) I then solve for n and I get n^2 + 3n - 2 = 0 My calculator produces results n^2 + 3n + 2 = 0. Is equation (1) the correct way to solve this problem? If it is, the I just have a sign error somewhere... but I've triple checked my work and it seems there is none, so I am assuming (1) is not correct. Any suggestions?