[davidw]

How long does it take? I earn an hourly rate such that $5 is not a lot of my time - perhaps it'd be more efficient simply to send them $5.

[federicof]

It's a fairly easy puzzle, for an average programmer it should take at most half an hour. Give it a shot :)

[davidw]

That's valuing my time at $10 an hour. No grazie:-)

[federicof]

Sure in this case you better send them the 5$, nevertheless please share this with friends or colleagues that may want to give their contribution while having fun for half an hour.

By the way, if you're an experienced programmer the solution is quite obvious, it should take less than 15 minutes. :)