Pattern Recognition Brain Teaser

37 Comments

1. Michelle B on November 25, 2006 at 2:07

   Sigh! Could not get this teas­er either. How­ev­er, I did get the clue (some­what). But what I found inter­est­ing is when I did repeat men­tal­ly the expla­na­tion, my brain felt, how can I say, a sense of well­be­ing, like it was being nour­ished. Are all brain teasers not cre­at­ed equal in this regard? I remem­ber men­tal dis­tress after doing oth­er ‘brain teasers’ years back.

   
   
   
2. Alvaro on November 26, 2006 at 10:45

   Hi Michelle, you are prob­a­bly expe­ri­enc­ing the release of dopamine and oth­er neu­ro­trans­mit­ters that cre­ate that sense of well­be­ing as you iden­ti­fied a pat­tern. Which is why learn­ing, brain teasers, trad­ing suc­cess­ful­ly, and oth­er “brain exer­cise” activ­i­ties can be quite addictive!

   A dif­fer­ent appli­ca­tion, but illuminating
   https://sharpbrains.com/blog/2006/10/13/the-joy-of-giving-and-the-cognitive-and-emotional-health-project-the-healthy-brain/

   
   
   
3. Maryanne Silber on November 27, 2006 at 7:06

   Looked at the prob­lem dif­fer­ent­ly. I did­n’t get your solution…but I had fun. I said 7+4+8=19
   3+9+7+19
   6+5+10=21
   9+4+8=21

   In try­ing to make a sec­ond “pair” that were equal I put 9 in your emp­ty spot.

   Well…I’v always been bad at math and any form of log­ic. But I had fun!

   
   
   
4. Maryanne Silber on November 27, 2006 at 7:08

   OOOPS…I can’t type either.
   3+9+7=19 also “I’ve”

   
   
   
5. Caroline on November 28, 2006 at 11:58

   Maryanne,

   While the dopamine rush that Alvaro men­tions above hap­pens when you solve the puz­zle or under­stand the answer (the “aha!” moment), work­ing through the puz­zle is good brain exer­cise in and of itself (you’re get­ting chal­leng­ing and nov­el men­tal stim­u­la­tion). And you did your math cor­rect­ly with a log­i­cal pat­tern, so you’re not that bad at either task! The typos … well those may be more due to a lapse in atten­tion and hand-eye coor­di­na­tion. Keep work­ing and hav­ing fun with it!

   
   
   
6. shreyas on November 29, 2006 at 10:43

   came up with some­thing dif­fer­ent, in terms of a rela­tion­ship. sub­tract each num­ber from 9, take the absolute val­ue of this dif­fer­ence, and sum them, the total is always 8 ie. 7–9=-2=2 (absolute), 4–9=-5=5, 8–9=-1=1 so 2+5+1=8
   sim­i­lar­ly in the sec­ond and third rows, sum is 8. there­fore the num­ber in the fourth row can be either 7 or 11.
   con­vo­lut­ed solu­tion and non-unique.
   won­der what that says abt my brain!

   
   
   
7. Caroline on November 29, 2006 at 10:58

   You’re right, that does fol­low a pat­tern! Both you and Maryanne are find­ing cre­ative solu­tions, which is good exer­cise for your brain! I think it says that your frontal lobes are in good shape — good work!

   
   
   
8. Randy on December 16, 2006 at 11:40

   This clue con­fused me:

   If you do your fig­ures from east to west,

   would­n’t that mean from right to left?

   
   
   
9. Caroline on December 18, 2006 at 2:40

   Good­ness Randy — you’re right! I’ll change it now!

   
   
   
10. joseph knecht on January 21, 2007 at 3:29

    An alter­nate solu­tion, since the prob­lem does­n’t state that the num­bers must be integers:

    If the first num­ber is greater than the sec­ond num­ber, add them and then sub­tract the dif­fer­ence of the first and sec­ond num­ber. This cov­ers row 1 and row 3.

    If the first num­ber is less than the sec­ond num­ber, then add them and then sub­tract one less than the dif­fer­ence. This cov­ers row 2, and indi­cates 2.5 as a solu­tion to row 4.

    
    
    
11. Caroline on January 22, 2007 at 12:42

    Joseph,

    Inter­est­ing solu­tion, but if you don’t know what the first num­ber in line 4 is, how do you know which rule to fol­low (the rule for lines 1 & 3 or the rule for line 2)?

    
    
    
12. joseph knecht on January 22, 2007 at 3:59

    Car­o­line,

    Luck­i­ly for me, there was no solu­tion where the first num­ber is greater than the sec­ond number.

    
    
    
13. Caroline on January 29, 2007 at 11:19

    Joseph,

    You’re right. The solu­tion for the first num­ber being larg­er does­n’t make sense (I end up with 16=4). If the first num­ber is small­er, it does work out, but I get 1.5 as an answer.
    x+8-(8‑x-1)=4
    x+8–8+x+1=4
    2x+1=4
    2x=3
    x=1.5

    Nice solu­tion! Com­pli­cat­ed, but it works!

    
    
    
14. joseph knecht on February 3, 2007 at 8:25

    Car­o­line,

    Right you are! Thanks for the correction.

    
    
    
15. john on February 10, 2007 at 6:57

    1
    11
    21
    1211
    111221
    312211
    ? whats next

    
    
    
16. Alvaro on February 12, 2007 at 5:46

    per­haps

    13112221?

    good one!

    
    
    
17. Michael on April 29, 2007 at 7:12

    i found a dif­fer­ent solution
    7*4=2 8
    3*9=2 7
    6*5=3 0, the impor­tant dig­it is only the last dig­it therefore
    3*8=2 4, now 6 may have worked but each pair has an odd and an even num­ber plus no pair is dou­ble digit.

    
    
    
18. Caroline on April 30, 2007 at 12:36

    Cre­ative Michael! Fol­low­ing your rules, I get 3 and 8 as pos­si­ble answers, with­out a way to choose one answer. In line 2, both 3 and 9 are odd, so keep­ing it even and odd in each line does­n’t work. If you can come up with anoth­er rule to make only one answer, it’ll work!

    
    
    
19. Kelly Stewart on August 28, 2007 at 3:26

    I did­n’t get the cor­rect answer. I got five. the way I came to this was by adding the first and third num­ber in each row. then you take that answer and sub­tract 1 from the num­ber in the “one’s” spot. excuse my lack of knowl­edge. the num­ber 123 1 is the hun­dreds, 2 is the tens, and 3 is the ones. so sub­tract 1 from the ones place and I came to the answer 5.

    
    
    
20. icanrule on November 28, 2007 at 5:09

    I came up with 3 but I got it in a dif­fer­ent man­ner. Here is the way I fig­ured it out. 

    1. 7 x 4 = 28 and Sub­tract first num­ber = 8
    2. 3 x 9 = 27 and sub­tract the first num­ber = 7.
    3. 6 x 5 = 30 and sub­tract first num­ber but since num­ber can’t be zero make it 10.
    4. 3 x 8 = 24 and sub­tract the first num­ber = 4. 

    Although the 3rd rule does­n’t jive all that well it still works.

    
    
    
21. MomV on December 2, 2007 at 11:08

    Pat­tern Recog­ni­tion …C is the answer I picked.

    
    
    
22. dunc on December 19, 2007 at 1:33

    i came up with

    (7×4)-20 = 8

    (3×9)-20 = 7

    (5x6)-20 = 10

    (3x8)-20 = 4

    go fig­ure..

    
    
    
23. Erin on December 31, 2007 at 2:09

    dorks.

    
    
    
24. Alvaro on December 31, 2007 at 5:00

    Hel­lo Erin, I wish you the best in 2008, per­haps includ­ing a more will­ing atti­tude to take on chal­lenges and, if you decide not to give it a try, not to insult oth­er peo­ple in that defen­sive, unhelp­ful way. No one is perfect :-)

    Have a great hol­i­day and we hope to see you around again.

    
    
    
25. Ines on January 26, 2008 at 7:03

    I thought the exact same way as Michael, and icansure:

    1. 7 x 4 = 28 and Sub­tract first num­ber = 8
    2. 3 x 9 = 27 and sub­tract the first num­ber = 7.
    3. 6 x 5 = 30 and sub­tract first num­ber but since num­ber can’t be zero make it 10.
    4. 3 x 8 = 24 and sub­tract the first num­ber = 4.