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Difficult logic series. Please help!

  1. Oct 6, 2009 #1
    Dear Forum Users,

    I came across these three logic series' and as I was unable to resolve them, I thought about posting them here. Maybe you know the correct answers and care to explain? Sorry for the bad quality, but you should be able to recognise the patterns.


  2. jcsd
  3. Oct 6, 2009 #2
  4. Oct 7, 2009 #3
    1. B
    2. E
    3. D

    Explanations will follow if you're interested. Did you take these with your phone during an IQ test?
    Last edited: Oct 7, 2009
  5. Oct 8, 2009 #4

    thank you very much for your response. yes I did take these pictures off a computer screen, so sorry for the bad quality.

    If you don't mind I'd be very interested in the explanation,

    thanks a lot,
  6. Oct 8, 2009 #5
    1) are the number of corners relevant?


    2) it's either d or e but which one makes sense?


    3) do the squares follow a certain pattern?

    Last edited by a moderator: Apr 24, 2017
  7. Oct 8, 2009 #6
    1 (the one with the boxes):
    Look at the columns as equations.
    An empty square plus a black square changes it to a highlighted square, while an empty square plus a highlighted one changes it to a black square. A highlighted square plus a black square forms an empty square. Any square plus a similar square retains its type.

    2 (the one with a bunch of arrows in the answer choices):
    By looking at the last three boxes you can tell that the trapezoid is going to move around the edge of the square and go counterclockwise. D or E could be potential answers then since both account for that movement. The arrows explain how the semicircle will be warped. Since it is acted on in more than two directions during the next three images, E--the answer with three arrows in it--accounts for this change.

    ...I can't remember why I picked D, sorry. The only reason I could think of for it now was that its the only choice that has shapes similar to the sequence above in it and a star. I could just as easily say that the answer is E though and argue that the small star in boxes 2 and 4 adds a point to the big star.
    Last edited: Oct 8, 2009
  8. Oct 8, 2009 #7
    thank you very much for your explanation,

    I understood the one with the boxes, but I'm afraid I'm still confused by the arrow figure.
    Do you mean that the arrow with the three arms points to the position of the rounded figure in the next three images?

    thanks a lot,
  9. Oct 8, 2009 #8
    I meant the directionS that the semicircle would be streched.
  10. Oct 8, 2009 #9
    Yep. The way I looked at it was that each column of individual squares will have either ALL the same types or ALL different types.

    I dunno-- I'm not sure I follow this either. D & E are the "obvious" choices, since they have the trapezoid in the correct orientation (assuming it's sort of rotating counter-clockwise). But the warping part doesn't make sense to me. It would seem you're suggesting that it gets warped in 3 different ways, I assume you mean to imply that the left-most is the starting position from which it gets warped? To me, it's getting warped in 4 different ways from the left box to the middle box. And two ways from the middle to the middle-right, and two ways again from middle-right to far-right. Plus, I don't follow how an arrow would really indicate a warping action.

    This one is actually A-- it was the only straightforward one to me. Count the line segments.

  11. Oct 8, 2009 #10

    thank you very much for your input
    ad 1: I was suspecting something like that, thanks for pointing it out. every square contains 13 line segments.

    what do you mean by all the same or all different types? I'm not sure I follow

    the arrows still don't make much sense to me,

    thank you,
  12. Oct 8, 2009 #11
    Yup, you're correct. :uhh: I was too lazy to count the line segments haha. Think of it not so much as being warped in a specific manor, but that those are the directions that it's being streched in.
  13. Oct 8, 2009 #12
    There are 3 different types of squares: Empty (E), Filled (F), and Darkish (D). Looking at (say) the lower-left squares in each of the boxes in the first column:

    - The top box's lower-left square is Empty (E)
    - The middle box's lower-left square is Filled (F)
    - The bottom box's lower-left square is Darkish (D)

    So each of the 9 square positions within a column of boxes has 3 values-- the top box, the middle box, and the lower box. I'll call that a "Set" of boxes. Each Set must either:

    1) Contain all the same type of squares
    2) Contain NO identical types of squares

    Hence, the possible valid Sets (in order of Top, Middle, Bottom) are:


    The invalid Sets would be:


  14. Oct 8, 2009 #13
    Yeah, I think I understand what you're implying-- I just disagree. If we assume the left-to-right progression, the direction of the warp/stretch is different in each of the last 3 boxes. If we assume the boxes from left-to-right are A, B, C, D, E, then:

    From A -> C, the shape is stretched horizontally, goes from flat to concave on the left side, and has reduced convexity on the right side.

    From C -> D, the shape shrinks vertically, the left side goes from concave to convex, and the right hand side goes from.

    From D -> E, the shape is stretched vertically, possibly stretched horizontally, goes from convex to concave on the left side, and goes from flat to convex on the right side.

    So, this makes things bizarre. If you put arrows in B, which imply the direction between A -> C, then why aren't there similar arrows for C -> D and D -> E? And if it's governing all the latter transitions, then why put it 2nd in the list, and how would you determine the order of operations? To put it simply, everything about this line of reasoning strikes me as wrong. I think there's probably something more sinister going on.

  15. Oct 8, 2009 #14

    thank you very much for elaborating so patiently. I now understand what you meant and think it's a more intuitive approach. My problem is that I naturally look for horizontal patterns.

    Still wonder if there is a logic explanation to the arrow problem?

  16. Oct 9, 2009 #15
    For the arrow one I would say D was the answer.

    Reason being that in each of the pictures the object that isn't the trapezoid has a 180 degree rotational symmetry through a horizontal axis that bisects the object (where that axis lays in the plane of the picture).
    Last edited: Oct 9, 2009
  17. Oct 9, 2009 #16
    that makes more sense than my answer
  18. Oct 9, 2009 #17
    Ahh, that's a decent answer! I was hoping for something a little more interesting, but that certainly works.

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