If n is a positive integer, is n^3 - n divisible by 4?
I. n = 2k + 1, where k is an integer.
II. n2 + n is divisible by 6.
My answer was E. But the OG answer is A, and I'm confused about this. The question says n is a positive integer, but that k is simply an integer. So if k = 1, then you have a set of consecutive integers 2, 3, 4. If k = 2, then you have set 8, 9, 10. In any case, playing with greater numbers this is sufficient. But what if k = 0. Then you end up with 0, 1, 2. And that is not sufficient.
Although n is a positive integer, k is merely an integer (nonetheless, an integer that leaves us with a positive n.
Was this just a mistake in the OG or am I missing a crucial concept?
Thanks for your help!
I. n = 2k + 1, where k is an integer.
II. n2 + n is divisible by 6.
My answer was E. But the OG answer is A, and I'm confused about this. The question says n is a positive integer, but that k is simply an integer. So if k = 1, then you have a set of consecutive integers 2, 3, 4. If k = 2, then you have set 8, 9, 10. In any case, playing with greater numbers this is sufficient. But what if k = 0. Then you end up with 0, 1, 2. And that is not sufficient.
Although n is a positive integer, k is merely an integer (nonetheless, an integer that leaves us with a positive n.
Was this just a mistake in the OG or am I missing a crucial concept?
Thanks for your help!
