There are currently 33 questions on Mensa's "Online IQ Test" which I took for fun. I correctly answered 32 questions and understand why they are correct, but there is one remaining question (to which I only know the answer to because answers are hardcoded in the page's JS) whose answer I do not understand.

Can someone explain to me why the following is correct (question 11)?

Answer D in question 11 is correct, but why?

I'm not saying it shouldn't be correct - just that I don't understand why. I don't follow the progression at all.

  • 3
    $\begingroup$ With most 'IQ tests', it's more a matter of 'the person who invented the puzzle thought of this one particular undefined sequence, with a weird rule which is just as weird as any of the rules that could generate the other answers'. $\endgroup$
    – boboquack
    Oct 26, 2017 at 9:17
  • $\begingroup$ Yeah, I suppose. I just felt it was strange that I was able to figure out all of the other "weird rules" except this one. $\endgroup$ Oct 26, 2017 at 14:32

1 Answer 1


if we consider every image has a center. the first image has 2 lines, second image has 3 lines which is (2+1) and the third has 5 (3+2). so the final image can have 8 lines(5+3).

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    $\begingroup$ Maybe mention what that sequence is famously called? $\endgroup$
    – APrough
    Oct 26, 2017 at 14:27
  • $\begingroup$ Thanks! What I think threw me off was getting stuck on thinking the first image had just one line. $\endgroup$ Oct 26, 2017 at 14:29
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    $\begingroup$ @APrough if you're referring to the Fibonacci sequence, there's not enough data to know that this is one. 2, 3, 5, 8 are certainly part of a Fibonacci sequence which starts at one, but it could also be part of the following sequence: 2, 3, 5, 8, 12, 17, etc (which I think is more likely) $\endgroup$ Oct 26, 2017 at 14:35
  • $\begingroup$ I thought it was 1 line, 3 lines, 5 lines, and I answered C which was 7 lines (and also incorrect). $\endgroup$ Oct 26, 2017 at 14:39
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    $\begingroup$ @Octopus, because the first image isn't one line. I'm not claiming it is. I was just explaining where my mental block was. I was incorrect, but I didn't understand why I was incorrect. Now that it's been pointed out to me it seems obvious, but I needed help getting there. $\endgroup$ Oct 27, 2017 at 3:31

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