I think it is 13, because it is the only one they couldn't deduce themselves to.

Actually, the argument they give for 12 works equally well for 13, so they haven't given a good argument for 12, either.

Ah a trick question. Not eleven.

This is something that always pissed me off about ALL testing. There are always multiple solutions. I don't think my math tests ever specified which number system or groups we were supposed to use...I always gave test designers an F for lack of foresight.

42 is the answer to everything!
Because they fit into the polynomial
f(x) = x^9/11340 - x^8/252 + 29x^7/378 - 5x^6/6 + 3013x^5/540- 95x^4/4+ 36184x^3/567 - 6515x^2/63 + 28831x/315 - 32

@Scott - The questions asks what number comes next; if 0..2....9 work, 10 and 11 don't but 12 and 13 do... then 12 would be the correct answer to the question... just because 13 is a number (further) in the series doesn't eliminate the perfectly valid suggestion put forward in this wonderful cartoon.

I wonder... how far can anybody go with this... there's a fine line between valid (palindromes is just beautiful!) and stupid (i.e. the set of numbers that I have written down on this page) with (n^2+n+11 is prime) being somewhere in the middle... can somebody give valid reasons why any number from 10 - 99 could be acceptable answers?

And Pi is right out...

(e) A

I have this problem myself on tests with pattern-filling. For a multiple-choice question, I can make an argument for (almost) any of the options. The problem is finding the best/obvious argument.

If you consider the definition of sequence, the answer could be anything in any considered set containing the before mentioned elements, like, for instance, "your mom"

Hey...The answer is '0' i have reset the counter

the answer is 0, it is a sequence with period = 10

(a) 10

but a base 16 = 10 base 10... and so do the others...

Not YM. It's 10, 11 AND 12.

10, 11 and 12 are solutions. Now Your Mom.

Billy dösn't know sequences.