What is the Math.SE take on questions like http://math.stackexchange.com/questions/1064/perfect-set-without-rationals, whose answer, judging from the comment, is known to the OP?

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See also: meta.math.stackexchange.com/questions/241/… Note that it's explicitly-allowed practice on SO (per the FAQ) to answer your own question (pretty sure you don't get +15 rep for selecting it as the answer, though). –  Isaac Jul 28 '10 at 21:46
The asker knowing the answer is not the problem I have with this question. I downvoted it because it looks like the asker copied it from a homework assignment or test without putting any thought into it. –  Larry Wang Jul 28 '10 at 22:16
–  Larry Wang Jul 28 '10 at 22:17