Question

Show that exactly one of number n, n+2 or n+4 is divisible by 3.

Answer 1

Let n=4, then n+2=6 and n+4=8, 6 is divisible by 3

Let n=5, then n+2=7 and n+4=9, 9 is divisible by 3

Therefore if n is any +be integer then n, n+2 or n+4 is divisible by 3.