That was my first thought, araver. I knew I'd seen the puzzle somewhere, and so googled it: the thing is that the solution is there for all to see and the puzzle is dated 2006! So what I'm guessing is that somebody has brought the problem to school as a challenge, and that they're using your brain (def not mine) to work out the answer for them. There seems to be a run on schoolboy (or girl) point-collecting lately.