Re: A really hot rocket scientist could have done it in his head. (n/t)
I did it in my head but then I couldn't post the working, like you did. :-)
I took it simply. There must be an even number of birds, since they pair up, and an odd number of posts, since they keep having one left over.
I then tried the first few integers and quickly found a combination that worked.
it's like crossword puzzles and anagrams. I look at the question and the answer is obvious, but I can't explain why.
Something to do with beiong able to read upside down, back-to front, mirror writing, and even read my own handwriting?